Alvaro Morata scored just 31 seconds after coming on as a substitute but Champions League hopefuls Juventus had to settle for a 1-1 draw at Fiorentina.
Dusan Vlahovic scored his 17th Serie A goal of the season with a first-half penalty to put the relegation-threatened Viola in front at Stadio Artemio Franchi, after Adrien Rabiot handled in the area.
Juve boss Andrea Pirlo made a double substitution at the break and it was Morata, one of the two introduced, who levelled with a stunning strike in the first minute of the second half.
The reigning champions were unable to secure a Sunday afternoon victory that would have moved them into second place and fifth-placed Napoli had the chance to join them on 66 points if they beat Torino on Monday.
Fiorentina made a promising start and Wojciech Szczesny raced out sharply to deny number Vlahovic after Franck Ribery played the striker in.
Juve had a huge stroke of luck when a deflected long-range drive from Erick Pulgar struck the post and bounced into the arms of Szczesny, but Vlahovic gave the Viola a deserved lead just before the half-hour mark.
Referee Davide Massa pointed to the spot following a check on the pitchside monitor, with the ball having struck Rabiot's arm as he jumped to try and head clear, and Vlahovic made the midfielder pay with a cheeky 'Panenka' penalty.
Aaron Ramsey missed a good opportunity to equalise late in the first half when Fiorentina were opened up by a slick move and the Wales international poked wide at full stretch with only Bartlomiej Dragowski to beat.
Pirlo reverted from a three-man defensive set-up to a back four for the second half, with Morata replacing Leonardo Bonucci and Dejan Kulusevski on for Paulo Dybala.
Morata made an instant impact, getting on the end of a ball down the right channel and cutting inside sharply before picking out the far corner of the net with a sublime left-footed finish.
Juve looked a different side after the break and Nikola Milenkovic nodded clear to prevent Cristiano Ronaldo from tapping in Giorgio Chiellini's header across goal.
Ronaldo failed to head home a brilliant cross from Kulusevski six minutes from time as Juve dropped points in the battle for a top-four finish.