Milan looked headed for defeat on Saturday after Antonio Di Natale had given Udinese an early lead, but Lopez, on loan from Catania till the end of the season, came off the bench to net the equaliser, before setting up Stephan El Shaarawy's 85th-minute winner.
While he admitted he was happy with his personal contribution, Lopez also emphasised how important Saturday's victory was, especially as it came against one of their title rivals.
"I'm not just content, I'm really happy because scoring for this team has always been my dream," Lopez said on the club's official website.
"This win is important because it gives the team confidence to push forward.
"We have to continue to find momentum and to get the three points one game at a time."
Lopez also paid credit to El Shaarawy, who was a capable replacement for the suspended Zlatan Ibrahimovic on Saturday.
"El Shaarawy is young but he's growing a lot," Lopez said. "And this group is strong. Everyone gives their all when they get on the pitch."
Milan are next in action on Wednesday when they take on Arsenal in the Champions League, before they return to Serie A action on Sunday against Cesena.