Romelu Lukaku struck his 25th goal of the season but Inter Milan's title hopes stalled on Wednesday with a 3-3 draw against Sassuolo.
Inter, in third, are eight points behind leaders Juventus and four adrift of second-placed Lazio who travel to Atalanta later Wednesday.
"The draw hurts us," said Inter boss Antonio Conte.
"We had several chances to kill off the game. There is a lot of regret. If we look at the goals there is so much to be reviewed, small and big individual errors."
Conte's side got off to the worst possible start at the San Siro with Italian forward Francesco Caputo opening the scoring for the visitors after just four minutes.
Caputo, 32, punished some poor defending, picking up a Filip Djuricic cross to slide the ball past a stunned Samir Handanovic.
But a Jeremie Boga foul on Milan Skriniar allowed Inter to get back into the game as Lukaku stepped up on 41 minutes to score from the penalty spot.
Cristiano Biraghi then broke through following good work with Alexis Sanchez for the defender's first league goal for Inter in first-half stoppage time.
Inter could rue Roberto Gagliardini's spectacularly missed chance to give the hosts a two-goal cushion, hitting the crossbar in front of goal.
Three goals came in the final ten minutes with Domenico Berardi pulling Sassuolo level from the penalty spot on 81 minutes.
Lukaku had a goal ruled offside before Borja Valero latched onto an Antonio Candreva free-kick to tap in five minutes later.
But defender Giangiacomo Magnani bagged a point for 12th-placed Sassuolo with one minute to go.
Conte's woes were compounded by defender Skriniar being sent-off in extra time.
Lazio -- four points behind Juventus -- play Atalanta in Bergamo bidding to keep their bid for a first Serie A title since 2000 on track.
Roma, in fifth, host relegation-threatend Sampdoria in the Stadio Olimpico.
Romelu Lukaku has scored 25 times in all competitions for Inter Milan.