College basketball's main event this weekend ended in upset.

Kansas and Kentucky, the two winningest programs in college hoops history, put on a pretty good game in Rupp Arena. But the Wildcats, a flawed-but-dangerous team, one ranked fourth in the country but sure to take a steep drop in Monday's polls, were upset 79-73 by the second-ranked Jayhawks (19-2) as freshman Josh Jackson recorded 20 points and 10 rebounds.

Kentucky has lost two straight; the Wildcats fell at Tennessee on Tuesday. The win will stabilize Kansas come Monday's poll updates. KU was coming off a loss to West Virginia.

Kansas had 17 second-chance points, a zone defense that flummoxed the Wildcats (17-4) and a stabilizing presence in Jackson. He was the best player in the game, and he played 39 minutes. He looked more like a senior than freshman, and played like he was trying to earn a starting spot. Another typical development: Frank Mason III led Kansas in scoring (21 points).


1. No. 1 seed implications

I know you're probably up to speed on your bracketology, but just in case here was the situation heading into Saturday's game: Our Jerry Palm had Kansas as a No. 1 seed, the weakest of the four 1s. If you were thinking Kentucky was right there in the mix for a No. 1, you were mistaken. Kentucky was the strongest of the 3s, though.

This game and resume value for both teams meant a lot, of course. Kentucky needed it more, and had more to lose, because it was hosting and it plays in a far inferior conference and it lacked/still lacks top 40-type wins in comparison to Kansas. So this outcome will certainly have tangible effects come Selection Sunday, barring a double-digit winning streak.

The Wildcats have no chance of leapfrogging the Jayhawks for a No. 1 this season. KU is still in the driver's seat to land on the top line. Kentucky's 1-seed hopes aren't totally gone, but with a 1-3 record against the four toughest opponents they've faced (UCLA, North Carolina, Louisville, Kansas), and with only one of those games being on the road, it likely means Kentucky will need to run the table in order to have a valid resume to contend for a No. 1 seed. Even, then, I could see it not being enough.

And remember, Kentucky needed a 47-point performance from Malik Monk to beat UNC. It's still the best game of the 2016-17 season, that one.

2. Kansas went zone out of nowhere and Kentucky had nothing

With Kentucky in control, Kansas coach Bill Self opted to abandon his athletic team's man-to-man principles and hit the Wildcats with a zone. Kansas hadn't used a zone since December, and in fact, according to Synergy Sports, Kansas had played zone less than 5 percent of the time this season.

UK was totally twisted. Self said afterward that this decision decided the outcome.

The zone wasn't textbook, but it was effective. Monk started the game 5 for 5 from the field, then did not score a field goal from the 8:22 mark of the first half until 3:15 was left in the game. Monk finished with 18 points. Kentucky got some shots in the second half and was able to get decent second looks here and there, but the team had no flow.

Kansas effectively cut off Kentucky's routine, and it was the first time this season -- even including the Louisville game -- that Kentucky looked both rote on defense (KU continually got to the hoop and was available for second-chance points; this is an indictment, given Kansas was forced to play small) and out of rhythm on offense.

Josh Jackson played, for the most part, like a vet on Saturday. USATSI

3. Bam can't capitalize

Earlier this week, Cailpari said that if his players did not feed Bam Adebayo in the post, they'd be sitting on the bench. Adebayo had his chances, but he didn't come out of this with a performance that he'll submit to NBA scouts and GMS. He finished with 10 points, eight rebounds, three assists, two steals, four fouls and four turnovers. He was muted in part by the zone. He had just seven field-goal attempts. He really should have earned double that. He played 37 minutes. It was surprising to see him have merely an OK game. This was set up for him to thrive.

4. Never happened before under Calipari

Kansas joins UCLA as teams that have defeated the Wildcats at Rupp Arena this season. It's the first time since 2008-09 that Kentucky lost two games at home against nonconference opponents. That was Billy Gillispie's final year as UK coach.

I didn't think UK would fall again after that entertaining -- but not all that close -- 97-92 loss to UCLA. And considering Kansas didn't have Carlton Bragg available Saturday, it's all the more surprising. Calipari said afterward that his team didn't match Kansas' toughness. I have to agree. Kansas was consistently more poised and punched back almost every time Kentucky made a big play. Kentucky doesn't lack toughness, though. That's a motivational thing for Calipari, and he has evidence in this game. If you've seen UK play this year, you've seen a lot of talent, a lot of pizzazz, and still plenty of toughness. It's a matter of playing tough against the best, though.

5. Reminder: Kansas and Kentucky need to play every season

I was at that overtime epic in Lawrence last season. I wrote this column about why KU and UK have to play every season. They're already aligned to play once every three seasons on a neutral court in November due to the Champions Classic. So we'll get these two again in November at the United Center. Hopefully, in 2018-19 and 2019-20, the SEC/Big 12 Challenge can continue to schedule these programs. It makes the most sense and is best for the sport. Self and Calipari have a mini-rivalry of sorts, too, so it's all the better.

This wasn't even a top-10 game this season, or a top-10 game of January, and it was still really good and must-watch. I love the flavor of putting in late January, too, on a non-football weekend. Nice spotlight for the sport. Let's keep this in mind going forward. In years when they're not scheduled to meet in the Champions, Kentucky and Kansas should be playing games in each other's arenas.

6. Kansas wins sets up another huge game in college hoops

Because Baylor barely got by Ole Miss on the road on Saturday, we're going to have ourselves a top-five matchup yet again in just a few days. Kansas will almost certainly stay in the top five due to getting this road win and having so many other top 10 teams fall this week. Baylor, ranked fifth in the country, could shoot up to No. 2 after its win.

On Wednesday night, with first place in the Big 12 on the line, Baylor travels to Phog Allen Fieldhouse. The Bears have never won at Kansas under Scott Drew. It's been a huge season for BU, but if the Bears are able to pull off the upset there, it would be a historical event in the history of the school. That's not overstating it. A win there would put Kansas' 12-year Big 12 streak of dominance in jeopardy, practically bolt Baylor to the 1 line and completely change Drew's reputation among his harshest cynics in the process.

But almost no one not named Kansas gets out of the Phog with a W. So we'll see. Great for college hoops that this is coming right up, though. The Big 12 is fighting with the ACC to be called the best conference in the country.