Still without striker Mauro Icardi amid a contract dispute, Inter Milan lost 2-1 at Cagliari in Serie A on Friday and loosened their hold on a Champions League spot.
Inter remain third but only two points ahead of fourth-placed AC Milan and three ahead of fifth-placed Roma, who both play on Saturday.
It marked the fifth straight match that Icardi, Serie A's joint top scorer last season with 29 goals, has missed in all competitions since being stripped of the club's captaincy as he demands a contract extension.
Luca Ceppitelli put Cagliari ahead after the half-hour mark by redirecting a free-kick into the net with a fine header. Eight minutes later, Lautaro Martinez equalised for Inter, heading in from Radja Nainggolan's cross.
Leonardo Pavoletti then restored Cagliari's advantage with a low volley between two defenders.
Cagliari had a chance to extend their lead but Nicolo Barella's penalty attempt sailed high over the bar in stoppage time.
Cagliari sit 14th, nine points above the relegation zone. Milan hosts Sassuolo and Roma meet Lazio in the Rome derby.