Of the many truisms about playoff basketball, my favorite is that it is more about weaknesses than strengths. While a team can get through the regular season by doing things that work against most opponents most of the time, in the playoffs all that matters is the opponent in front of you. You must not only try to exploit every advantage you might have, but be clear-eyed about your disadvantages so you can anticipate how the other side will try to exploit them. 

With that in mind, here's a look at everything that happened in the opening weekend of the 2021 NBA playoffs, through the lens of a weakness the losing team must try to cover up. Think of it as the hater's guide to all eight games. 

1. Clippers revert to old ways at worst time

It's almost as if the Los Angeles Clippers wanted to make everybody write them off. They had a 98-95 lead halfway through the fourth quarter, then, in crunch time, lost all semblance of offensive flow and lost by a score of 113-103. The start of the game wasn't great, either, and coach Tyronn Lue lamented that they didn't put more pressure on the rim.

"Get to the paint or die trying," Lue said Sunday. "That's what we have to do."

The Clippers' offensive numbers in Game 1 look good. That does not, however, excuse all the times they settled for tough pull-up jumpers. While this is a historically great jump-shooting team, it is also the last one that should need to be reminded of the difference between the shots you can make and the shots you're looking for. They remember how they collapsed against the Denver Nuggets last season, and they've spent this season working on breaking their bad habits.

It was disheartening, then, to see George take a contested 3 over Dorian Finney-Smith with about two minutes left, down by three points. Lue has brought up the shot at both of his media availabilities since the loss. 

A couple of possessions after that, George attacked Luka Doncic off the dribble and dunked with two hands before help could get there. He and Kawhi Leonard had several nice interior passes over the course of the game, too. Going forward, though, Lue said he wants Los Angeles to "mix it up" more often: Take what the defense gives you, but don't let the defense off the hook. 

The presence of Rajon Rondo, who played the entire fourth quarter, has made the Clippers more organized. If they're looking for rim pressure, though, they should consider finding some minutes for Terance Mann

2. Lakers need space to jam 

Just like last season, the Los Angeles Lakers were an underwhelming halfcourt team during the regular season. It was easier to dismiss this concern this time, though, since this could be largely attributed to injuries and we'd already seen them overcome this issue to win a title.

About that. Los Angeles scored a grim 80.2 points per 100 possessions in the halfcourt against the Phoenix Suns on Sunday, per Cleaning The Glass. The Lakers once again started Andre Drummond at center and glued Marc Gasol to the bench. They shot 26.9 percent from deep, and, unlike their playoff opener against the Portland Trail Blazers in the bubble, it didn't feel like it was just bad shooting luck.  

The Lakers have a spacing problem, particularly when Drummond is on the floor. In theory, they can overcome this if LeBron James goes supernova and Anthony Davis shoots like he did last year. It helps if they crush teams on the glass and run circles around them in transition, too. Absolutely none of that happened in Game 1, though, and too many possessions ended with Davis clanking a jumper.

Davis shot 5 for 16 and blamed himself for the 99-90 loss, but this was a collective failure: Kentavious Caldwell-Pope and Wesley Matthews shot a combined 1 for 10 from deep, and Phoenix got away with packing the paint. Considering that Chris Paul was hobbled and the Suns shot poorly themselves, this was a missed opportunity. 

3. Denver has so much ground to cover 

The Nuggets were a good, not great defensive team in the regular season, but they didn't have much margin for error on that end. They defend pick-and-rolls aggressively, taking advantage of Nikola Jokic's anticipation and quick hands while protecting him from having to defend smaller players in space. When the Nuggets are at their best, Jokic is disruptive and his teammates are flying around, helping each other and communicating.

The flip side is that Denver is vulnerable to a team like the Trail Blazers. Damian Lillard and CJ McCollum can get the Nuggets in rotation whenever they want, and it's uncomfortable to be scramble mode when the floor is spaced and the shooters are always shot-ready. Portland shot 19 for 40 (47.5 percent) from deep, but it's not all about accuracy. Lillard and McCollum know that Norman Powell, Robert Covington, Carmelo Anthony and Anfernee Simons won't hesitate when the ball comes to them. 

Denver's defense improved throughout last season's playoffs, and the same could happen this time. This will be a challenge, though, if the Nuggets don't get healthier quickly. Jamal Murray was having his best defensive season before he tore his ACL, and Denver could sure use Will Barton and P.J. Dozier in this matchup. Gary Harris is not walking through that door. 

4. Regarding the Knicks' shot selection

While the New York Knicks have become a much more accurate 3-point shooting team under Tom Thibodeau, they are not a prolific one. They take a lot of midrange shots, and even though it has often seemed like Julius Randle makes every difficult jumper that he takes, the old-school shot profile has its drawbacks. In their 107-105 loss to the Atlanta Hawks on Sunday, Randle saw a crowd every time he touched the ball in the halfcourt and elected to take a ton of tough 2s.

Heading into the playoffs, the fear about the Knicks was that they didn't have another gear. They'd played their best players extremely heavy minutes in the regular season, and they always played hard. In the postseason, everybody does all this, so they can't afford to waste possessions or have dry spells. 

As great as New York's defense has been, it shot up the standings because it went on a tear offensively. In Game 1, Alec Burks' 27 points in 26 minutes on 9-for-13 shooting almost saved the Knicks, but they needed that performance to make up for Randle's 6-for-23 night. 

5. The Celtics, stagnating

Even last season, when the Boston Celtics had a more well-rounded roster, they could be baited into stagnant offense and contested jumpers. This year, this has happened much more often, for obvious reasons. Gordon Hayward is gone. Kemba Walker hasn't always been himself. Jayson Tatum has made strides as a lead playmaker, but still has some growing to do as a passer. Now that Jaylen Brown is out of the lineup, all of Boston's offensive problems are exacerbated, as opposing teams can focus even more attention on Tatum and Walker. The two combined to shoot 11 for 36 against the Brooklyn Nets on Saturday. 

Boston and Brooklyn both switched like crazy to try to prevent the other team from running its normal offense. The Nets' defense isn't elite, but they know how to scram out of mismatches and they make sure star players see lots of bodies. Kevin Durant's block against Tatum one-on-one at the beginning of the second half was awesome … 

… but he didn't do this alone -- look at how many Brooklyn defenders have their eyes on Tatum on these plays in the second quarter: 

There were times in Game 1 in which the Nets didn't play with much purpose on offense, either, but the Celtics have much less margin for error. They need quicker decision-making, more cutting and more paint touches if they're going to make Brooklyn be more selective about its switches. They also need to be relentless when it comes to attacking the Nets' weaker defenders. 

6. Miami loses paint battle

It's not that the Miami Heat can't get into the paint. It's that they don't always do it, and there aren't many guys on the roster who do. This was part of the appeal of Victor Oladipo. Alas.

On Saturday, the Milwaukee Bucks outscored the Heat 56-24 in the paint and attempted 14 more free throws. This is how Miami managed to lose a game in which it scored 60 points from the 3-point line and its opponent scored only 15.

The Heat got what they needed from Goran Dragic and Duncan Robinson. Jimmy Butler and Bam Adebayo, however, combined to shoot 8 for 37. It was a weird game all around, and losing by two points in overtime should not affect Miami's confidence about the matchup.

Milwaukee, however, is probably feeling pretty good about its defense, too. It never went small, opting instead to keep Brook Lopez around the basket and let the other four defenders manage things on the perimeter. Some of the 50 (!) 3-point attempts Miami generated were a result of Lopez dropping against pick-and-rolls and dribble-handoffs, but this wasn't enough to force Mike Budenholzer's hand. 

7. The Wizards know who they are, I guess?

Against this Philadelphia 76ers team, it is profoundly strange to see the Washington Wizards start Raul Neto next to Russell Westbrook and Bradley Beal, but, hey, they know who they are. The Wizards are all-in on offense and speed. Unfortunately, this Ish Smith block against Tobias Harris is not something they can count on:

The trade-off against is the same as it's been all season, even during the Wizards' unbelievable push toward the playoffs: They are constantly putting out fires on defense. A lot of things went right for Washington in the 125-118 loss -- Joel Embiid got in foul trouble, the Sixers' shooters were cold, Beal once again scored efficiently despite being hounded every second that he was on the floor -- but it wasn't nearly enough. 

One of their recurring defensive problems: The Wizards, who were one of the league's most foul-happy teams in the regular season, sent Embiid to the line 10 times in the second half. 

8. Offensive issues of postseasons past resurface in Utah

Maybe the Jazz just had one terrible night. This was far from the first time in the past few years, though, that their offense has turned ugly under playoff pressure. Utah scored 43 first-half points and shot 12 for 47 from deep in its 112-109 loss to the Memphis Grizzlies on Sunday, disorganized and discombobulated most of the way. 

Memphis' ball pressure was typically excellent. There is no excuse, however, for possessions like these: 

Some important context: Donovan Mitchell was a late scratch. Rudy Gobert and Mike Conley got into foul trouble, and Gobert fouled out in 24 minutes. But this was rough. Jordan Clarkson missed all eight of his 3-point attempts and made a bunch of questionable decisions. 

Based on the Jazz's incredible regular season, I bet this is an anomaly. If it happens again, though, uh-oh.