AC Milan moved top of Champions League Group E on Wednesday after beating Dinamo Zagreb 3-1 to get their first home win in Europe's top competition in nine years.
Olivier Giroud's penalty on the stroke of halftime and further goals from Alexis Saelemaekers and Tommaso Pobega were enough for Milan to leapfrog Dinamo into first place on four points.
Stefano Pioli's side are two points ahead of Salzburg in third after the Austrians drew 1-1 with bottom side Chelsea later on Wednesday.
"I think we could have scored more, been a bit more precise in the final pass. But we're very happy, it wasn't an easy match but we did well," said Giroud to Sky Sport Italia.
Milan are seven-time European champions but have only returned to the top table in recent seasons after years in the doldrums.
When Milan beat Celtic in September 2013, Mario Balotelli was in the attack and Massimiliano Allegri was coach. They were thumped in the last 16 by Atletico Madrid that season.
But the 'Rossoneri' appear firmly back in the big time. After winning Serie A last term want to make a mark again on the continent.
"The Champions League is the best competition, we want to do well in it and we want to get past the group stage," added Giroud.
"We're at the second match, we have four points and we're doing well."
Dinamo tried to frustrate Milan in a similar way to how they dealt with Chelsea in their opening day win. Ante Cacic's side did a good job in holding off the Italian champions until Josip Sutalo brought down Rafael Leao in the 43rd minute.
MILAN ON TOP
Giroud stepped up to the penalty spot and netted his fourth goal of the season, giving Milan the lead and opening up what had been a tight match.
Saelemaekers appeared to have broken Dinamo's resistance two minutes after the restart by heading home Leao's cross.
But nine minutes later the away side gave the match new life through Mislav Orsic, who rifled in a powerful finish from Bruno Petkovic's delightful flicked assist.
Milan were not rattled and sealed the points with a nicely-worked goal with 13 minutes remaining.
Theo Hernandez got to the byline before pulling back an inviting pass from which Italy international Pobega crashed in his first Milan goal off the underside of the bar.
Milan youth product Pobega's strike was also his first in the Champions League, after returning to his boyhood club following four years on loan at a series of Italian clubs.
It was a positive end to an evening which began with fan disorder, with police confirming to AFP that a Croatian fan was stabbed near the San Siro before the match.
Police in Milan said earlier that 36 Dinamo fans had been intercepted, with 23 charged "for a variety of offences" and 20 handed stadium bans.
A video published on social media appeared to show a group of Dinamo supporters dressed in black and making Nazi salutes as they made their way towards the stadium.