The Steelers continued a disturbing trend with a fourth loss to a team with a sub-.500 record, as the Chargers dominated third down on both sides of the line in a 34-24 win Sunday afternoon at Heinz Field.

The Steelers are 7-6 and still clinging to hopes of securing the sixth and final AFC playoff spot, and it helps that the AFC North-leading Baltimore Ravens (9-4) and the Cincinnati Bengals (7-6) also lost. The Steelers visit the Dallas Cowboys (7-6) next week and have a showdown at home with the Bengals Dec. 23.

The Chargers, who have played poorly enough this season that it has been reported that San Diego coach Norv Turner and general manager A.J. Smith will be fired at the end of the season, improved to 5-8.

"That was an unfortunate poor performance by us, and by us I mean all of us,'' Steelers coach Mike Tomlin said during his post-game press conference. "We coached poorly today and played poorly today. It's a shame, given the opportunity that was in front of us, but it is what it is. We don't seek comfort. We accept responsibility for it.

"Hopefully, we can make corrections and move forward, because regardless of what happens in other stadiums, if we play the way we played today it does not matter. ... Obviously, today was a failure. We lost situational football, didn't convert enough third downs, particularly some short-yardage ones. ... And, obviously, they converted too many (on the Steelers). So, it was a good performance by them and a poor performance by us.''

The Steelers converted just 5 of 13 third-down opportunities, including 2 for 9 in the first half. The he Chargers were 12 for 22 (55 percent). This led to poor field position for the Steelers from the outset. Their first-half possessions began on their 20-yard line, 8, 21, 9, 7 and 11 until their final two possessions of the half.

"We had many chances to get a few first downs and flip the field position on them, but we couldn't convert,'' Steelers tight end Heath Miller said. "That was the difference in the entire game, but it was crucial in the first half. We were fortunate to be losing by only 10 points at halftime.

"But we put our defense in a poor position the entire half. It's a credit to our defense that they kept the game close, so we need to do a better job chipping it out of our territory. Even if we don't get a touchdown, we have to at least get some first downs and punt it far enough to give our defense a chance.''

Two points, two possessions: The Steelers scored late in the third quarter to trail 27-10 and had a couple of quick scores in the fourth quarter. However, despite a chance to get within two scores with the help of a two-point conversion, Tomlin did not try one.

"Until we stopped them, it was going to be insignificant,'' Tomlin said. "So, I was holding the two-point plays for that reason and that reason only. Now, we still have them in our hip pocket. ... We didn't want to put them on tape, unless we had an opportunity to close the game.''

When the game turned: The Chargers drove 78 yards in 17 plays and 9:32 to open the second half, as quarterback Philip Rivers converted three third-down plays, including a third-and-13. Running back Ronnie Brown scampered 17 yards on a draw to get into the red zone. Rivers' touchdown pass came on third down as well.

The Steelers began their initial second-half possession on their own 8-yard line, and quarterback Ben Roethlisberger fired a sideways pass toward Antonio Brown on first down. It caromed off rookie tight end David Paulson's backside into the end zone. Brown couldn't cover it, but Chargers cornerback Quentin Jammer did for a touchdown. In just eight seconds, the Chargers' 13-3 halftime lead ballooned to 27-3.

Highlight moments: Steelers wideout Mike Wallace, who has suffered from a number of dropped passes this season, including two in the first half, came on strong to finish with seven catches for 112 yards and two touchdowns. His 40-yard connection from Roethlisberger got the Steelers back in the game for a bit.

Cursed: The Steelers suffered another injury to a starter, as offensive guard Willie Colon's left knee was re-injured and he couldn't finish the game. Colon had missed the past two games, but he tried to come back against the Chargers.

Curse broken: The Chargers beat a team with a winning record for the first time all season by defeating the Steelers, but it also marked the first time San Diego has won a regular-season game in Pittsburgh after going 0-14. The Chargers did win the AFC Championship game in Pittsburgh during the 1994 season.

Top-shelf performances:

  • Wallace -- He was targeted 11 times and came through with his best performance this season after admitting publicly last week that he occasionally loses focus during a game since he rarely gets targeted as much as he used to. Wallace scored on a big play, but he dropped a pass that could have been a big play as well in the first half.

     
  • Roethlisberger -- After missing three games with a shoulder injury, he was 22-for-42 for 285 yards and three touchdowns with two sacks and an interception. He had a quarterback rating at 87.9.

     
  • Rivers -- He completed just 21 of 41 passes for 200 yards, but had three TD passes, just one sack and no picks. His rating was at 89.5.

     
  • Steelers ILB Lawrence Timmons -- He tallied 11 solo tackles, including one behind the line.

What they said about the loss:

  • Wallace -- "It's unbelievable, when you think about it. It's like we keep tripping over our own feet. It's not so much what they were doing, although they played a great game, but if we eliminate our mistakes and take care of the simple things I think we could be a much better football team.''

     
  • Steelers RB Isaac Redman -- "We played one of our worst games of the year, and we just can't keep doing this. We go out and play hard one week, and the next week we come out and have a performance like this. It's just not Steelers football. (So), we've just got to buckle down and execute and calm down and not get too overwhelmed when things aren't going our way.''

     
  • Steelers ILB Larry Foote -- "You can label this game any way that you want, but I've been in this league a long time and we just got whipped today. There are no excuses. They just beat us today. The biggest thing was third down. We didn't execute. We didn't get them up front, and we didn't do the job on the back end. So, all of us on defense were responsible. We gave up way too many first downs.''

Numbers you should know: Steelers PK Shaun Suisham hit a 49-yard field goal to close the first half to make his 14th straight kick this season. His career-best is 15 straight. Suisham is 24 for 25 this season with his lone miss coming from beyond 50 yards. ... Steelers punter Drew Butler boomed a 79-yard kick to the Chargers 1 in the second half. It's the second-longest in team history after Joe Geri's 82-yarder in 1949. ... The Steelers ran for just 69 yards, but Roethlisberger had 31 of them.

Injury update: Steelers -- OG Willie Colon re-injured his left knee early and did not return. He missed the past two games with a knee injury. Tomlin said that FS Ryan Clark (hip), WR Emmanuel Sanders (shoulder) and SS Troy Polamalu (Achilles) also suffered re-injuries. ... Chargers: DE Vaughn Martin (groin) and ILB Demorrio Williams (ankle).

Going forward: Steelers -- They travel to Dallas for a Dec. 16 matchup with the Cowboys in the final regular-season road game. The Steelers close out the season with home games against Cincinnati (Dec. 23) and Cleveland (Dec. 30). Chargers -- They have a home game against Carolina on Dec. 16.

Follow Steelers reporter Chuck Finder on Twitter @CBSSteelers and @cfinder.