AC Milan progressed to the last 16 of the Europa League on away goals after struggling to a 1-1 draw at home to Red Star Belgrade on Thursday, with the visitors playing the final 20 minutes with 10 men as the tie finished 3-3 on aggregate.
Milan took the lead in the San Siro in the ninth minute from the penalty spot, with Franck Kessie converting after Mark Gobeljic had handled in the penalty area.
But for the third time in the tie, Red Star levelled the aggregate scoreline as El Fardou Ben Nabouhane equalised in the 24th minute, with the visitors more than matching their illustrious opponents for the rest of the first half.
Even with Red Star going down to 10 men, as they did in the first leg, after Gobeljic was sent off for picking up his second yellow card, they continued to create the better chances.
Milan were forced to withstand late pressure but they held on to book a spot in the next round. Their unconvincing form continues, however, as Stefano Pioli's side remained without a win in their last four games in all competitions.
"The most important thing is passing through and this should give us the confidence but that tonight was a bit of a failure," Milan midfielder Rade Krunic told Sky Sport Italia. "We are not happy with the performance."
Red Star came into the contest unbeaten since the end of October in all competitions, but they appeared to be up against it after the referee, following a VAR check, awarded the early penalty.
Not long after Kessie had slotted home, Nabouhane thought he had equalised only to see his back-post finish ruled out. He did make one count soon after, though, firing a fine left-footed finish past Gianluigi Donnarumma.
Zlatan Ibrahimovic came on at half time, but a determined Red Star, roared on by coach and former Inter Milan player Dejan Stankovic, would not lie down, continuing to go toe-to-toe with the seven-times European Cup winners.
"I know what we did in 180 minutes," Stankovic told Sky Sport Italia. "I do not cry, the players have shown that we can do great things.
"Milan must improve. Right now the Scudetto is in the hands of Inter."
Milan face AS Roma in Serie A on Sunday as they look to keep pace with leaders Inter, who hold a four-point advantage over their rivals.