Inter Milan has been referring to its postponed match against Bologna as an opportunity to gain distance in the championship race for four months.
However, a goalkeeping error gave Bologna a 2-1 win on Wednesday, as Inter blew a lead and a chance to reclaim the Serie A lead.
With four games remaining, defending champion Inter was two points behind city rival AC Milan.
Ionut Radu, the reserve goalkeeper, was called into action for the first time in nearly a year after Samir Handanovic suffered a back injury, and he was to blame for Bologna’s winner.
Attempting to clear after a throw-in, Radu instead kicked the ball toward his own net, where Bologna’s Nicola Sansone added the finishing touch.
Marko Arnautovic, a former Inter Milan striker, headed in the equalizer for Bologna after Ivan Perisic had put Inter ahead early on.
The match was rescheduled from January due to a coronavirus outbreak among Bologna’s players.
In two other postponed matches, Fiorentina and Atalanta also squandered chances to improve their chances of qualifying for Europe.
Udinese defeated Fiorentina 4-0 at home on Saturday, the Viola’s second consecutive defeat.
Udinese (12th) got goals from Pablo Mari, Gerard Deulofeu, Walace, and Destiny Udogie.
Atalanta had to scramble for a 4-4 draw against Torino at home, with Luis Muriel converting his second penalty of the night in the 84th minute.
Torino is ranked eleventh.