Leverkusen's seventh league win on the bounce kept them 10 points clear of serial champions Bayern Munich with eight games to play in their quest for the club's first ever Bundesliga crown.
"It was a good performance, a deserved victory. It's not easy to win in Freiburg but we keep going," Leverkusen coach Xabi Alonso told DAZN before praising the performance of his playmaker Wirtz.
"It's not just the goal he scored, he has a super game. He has real quality and I am very happy for his development."
Wirtz, one of Leverkusen's key performers this season, got things moving in style. The Germany forward cut in from the left and unleashed a perfect shot with his right foot, chalking up his seventh league goal of the season.
The early goal stunned Freiburg, who came into the game fresh from a 5-0 thrashing at the hands of West Ham in the Europa League, with Leverkusen to face the Londoners in the quarter-final of the competition next month.
Freiburg responded against the run of play though, with Japan forward Ritsu Doan exchanging passes neatly with Lucas Hoeler to drill a low shot beyond the unsighted Lukas Hradecky.
Leverkusen put their noses back in front before half-time though, with Adam Hlozek tapping into an empty net after a mistake by Freiburg keeper Noah Atubolu.
Patrik Schick put the gloss on another convincing victory for Alonso's team, with a sensational finish to a scintillating Leverkusen counter-attack.
Jeremie Frimpong's cross from the right was caressed into the top corner by the Czech striker, who was the Leverkusen hero on Thursday with two stoppage-time goals against Qarabag in Europe.
Yannik Keitel pulled one back for Freiburg but the damage was already done, leaving the hosts in ninth and with European qualification slipping away.
