In-form Southampton ended Coventry's six-match winning run with a 2-1 victory at the CBS Arena.
Flynn Downes pounced on a rebound to open the scoring shortly after half-time before Kuryu Matsuki doubled Southampton's lead with five minutes remaining.
Victor Torp's stoppage-time penalty gave Frank Lampard's side hope in the final moments, but the Sky Blues were condemned to just their second home defeat of the season.
It meant that Tonda Eckert's side kept pace with sixth-placed Wrexham in the race for the play-offs as Saints extended their unbeaten run in all competitions to 12.
Second-placed Middlesbrough's faltering promotion push suffered another blow as Adam Randell's 96th-minute header earned Bristol City a 1-1 draw at the Riverside Stadium.
Kim Hellberg's side thought they were heading for a much-needed victory when substitute Leo Castledine opened the scoring with a 65th-minute strike.
However, Randell headed home Tomi Horvat's corner deep in stoppage time.
Middlesbrough have failed to win any of their last four home games.
Millwall boss Alex Neil was left fuming with the sending off that allowed lowly Blackburn to earn a surprise 2-1 win at The Den.
Luke Cundle's superb bicycle kick from Femi Azeez's cross gave Millwall the lead early in the second half.
But left-back Zak Sturge was dismissed just before the hour mark for a foul on Yuki Ohashi as he tried to burst through on goal.
Blackburn substitute Mathias Jorgensen scored twice in the last 10 minutes as Millwall dropped to fourth, two points behind Middlesbrough.
"If you're going to take your next step into the box to potentially shoot unopposed, my understanding of the rules is that's then a goalscoring opportunity," Neil said.
"I don't think he would have got that far to get there and get that opportunity to score, so in my opinion, I didn't think it was a sending-off."
Ipswich climbed to third place as goals from Ivan Azon and Jack Clarke earned them a 2-0 victory at relegated Sheffield Wednesday.
