But Kansas City and Jacksonville both fell to 5-4 with losses Sunday.
The 49-41 loss could deal a fatal blow to the Bengals' chances of repeating the franchise's lone playoff appearance since 1990.
While the Bengals were blowing a 21-point lead to the Chargers, the Baltimore Ravens rallied from a 26-7 deficit at Tennessee to win 27-26. The Ravens are now 7-2, three games ahead of the second-place Bengals, now 4-5 and losing their fifth in six games after a 3-0 start. Cincinnati had better not look back, either, because Pittsburgh and Cleveland are closing in.
The Browns upset Atlanta, and the Steelers knocked off New Orleans on Sunday to improve to 3-6 -- just one game behind the Bengals.
The combined record of the remaining Bengals opponents is 37-26. The Saints are 6-3.
"We're sitting at 4-5 right now," said quarterback Carson Palmer, who threw for a single-game career high 440 yards in the loss. "We have a heck of a schedule in front of us. It's a tough situation to be in. There's some adversity we haven't faced yet.
"A lot of guys need to come together and keep playing and keep fighting and try to scrape our way to the playoffs."
The Bengals gave up 42 points in the second half, the most allowed by a Bengals team in franchise history. Buffalo scored 41 in a half Sept. 9, 1979 in a 51-24 loss.
"We have to win a game," defensive tackle John Thornton said. "Before, we never even talked about the playoffs, and now that's all people want to talk about. We just need to get back to doing what we used to do -- just win games."
The Bengals need to run the table at 7-0 to match last season's 11-5 record. Palmer remained optimistic.
"We're not out of it," he said. "We have just as good a shot as any (team). We could end up 11-5 if we go on a run. You never know what can happen in this league. You might get into the playoffs at 9-7. You don't know right now, and we don't care. We're going to worry about New Orleans and then whoever is next on the schedule."
That would be the Browns at Cleveland.