SAN DIEGO -- On a stage where the Cincinnati Bengals needed a victory to keep their playoff hopes alive, quarterback Andy Dalton showed a flair for improvisation.
Dalton's 6-yard touchdown run with 4:11 remaining lifted the Bengals to a 20-13 victory over the reeling San Diego Chargers on Sunday before 54,980 at Qualcomm Stadium.
"To come here and get a win on the road is huge," said Dalton, who completed 25 of 39 passes for 211 yards with a touchdown toss and two interceptions. "That's what we had to do."
The win moved the Bengals, who captured their fourth in a row, within two games of the AFC North-leading Baltimore Ravens, who lost to the Pittsburgh Steelers on Sunday. The Bengals (7-5) and Steelers are tied for second in the division.
Dalton's game-winning scramble occurred after he couldn't find anyone open.
"It was actually a screen, but they had it defended pretty good," he said. "I thought I was going to be able to throw it quick somewhere, but I wasn't able to, so I just found a lane and was able to get in.
"Not everything is going to go exactly as you plan. It's what you do when everything breaks down. It was a big play, and we needed it at that point. It was great to get a touchdown right there."
The Bengals added a 24-yard field goal by Mike Nugent with 2:47 left after defensive end Carlos Dunlap forced a fumble by San Diego quarterback Philip Rivers and recovered it at the Chargers' 13 with 3:54 remaining.
The Chargers had a chance to tie the score in the final minute, but on fourth-and-10 from the Cincinnati 17, safety Reggie Nelson intercepted a Rivers pass in the end zone.
The Bengals' defense blanked Chargers in the second half, and it kept the San Diego offense out of the end zone the entire game. San Diego's lone touchdown came courtesy of a 31-yard interception return by Demorrio Williams early in the second quarter. The Chargers also got two first-half field goals by Nick Novak, but that was it.
"We showed our heart today," Dunlap said. "They had a couple of long drives on us, but we didn't let them get into the end zone. That is one of those things (defensive coordinator Mike) Zimmer has been pounding in us since camp."
The loss was a huge setback for the Chargers. They stumbled to their fourth consecutive defeat and are in danger of missing the playoffs for the third straight season, which might spell the end for coach Norv Turner. The job status of general manager A.J. Smith also could be in jeopardy.
Denver's win over the Tampa Bay Buccaneers clinched the AFC West title for the Broncos, giving them a five-game cushion on San Diego (4-8) with four games remaining. San Diego sits three games out of the final AFC wild-card position.
"We're all upset and everyone is down, but this is the NFL, and we have another game coming up next week," said San Diego wide receiver Danario Alexander, who finished with six catches for 102 yards. "We have to come out and play and try and get another win. We just have to look forward to playing our next game."
"You get frustrated," Chargers linebacker Shaun Phillips said. "You've just got to keep playing football. We signed up for 16 games. We're going to go out and play for 16 games. The only thing that's guaranteed is next week, and that's all we can worry about."
Cincinnati scored on its opening drive as Dalton connected with tight end Jermaine Gresham on a 19-yard scoring pass for a 7-0 lead. The 91-yard, 16-play drive consumed 7:21.
The Chargers cut the deficit to 7-3 on a 20-yard field goal by Nick Novak with 14:57 remaining in the second quarter.
Less than a minute later, Williams' interception return gave the Chargers a 10-7 advantage. It was the second time this season Williams intercepted a pass and cashed it in for a score. He also had one in the Chargers' 31-13 win over the Kansas City Chiefs on Nov. 1.
The Bengals tied the score on a 19-yard field goal by Mike Nugent with 9:38 remaining in the second quarter.
Novak booted a 19-yard field goal for a 13-10 San Diego lead at the end of the half.
NOTES: The Chargers still hold a 19-13 record in the series against the Bengals. ... Cincinnati hadn't won in San Diego since 2003, when it claimed a 34-27 victory. ... In the teams' previous meeting, in 2010, the Bengals took a 34-20 decision. ... Chargers tight end Antonio Gates remains one touchdown catch shy of Lance Alworth's club record of 81. Gates had six catches for 49 yards but no touchdowns Sunday. ... The Bengals' inactive players were wide receivers Mohamed Sanu and Armon Binns; cornerback Jason Allen; safety George Iloka; defensive tackles Devon Still and Brandon Thompson; and tight end Richard Quinn. ... The Chargers' inactive players were wide receivers Eddie Royal and Micheal Spurlock; safety Darrell Stuckey; linebackers Jarret Johnson and Donald Butler; tight end Dante Rosario and defensive tackle Aubrayo Franklin.