Donyell Malen's second-half goal salvaged a point as Borussia Dortmund were held at local rivals Bochum 1-1 on Saturday.
Dortmund fell behind early as Bochum's Kevin Stoeger unleashing a rocket from the edge of the box to catch the visiting defence off guard.
Malen replied early in the second half, his third goal in his past three matches, to level the scores.
The goal sparked Dortmund into action but Bochum held firm. English teenager Jamie Bynoe-Gittens had a late chance to win it for the visitors, but he missed from close range.
Despite the point, the draw raises more questions for Dortmund coach Edin Terzic, with his side's attacking riches failing to find fluency up front.
Dortmund goalie Gregor Kobel said Bochum "overran us in the first half."
Captain Emre Can admitted that "a lot is missing" from his side's performances at present.
Wirtz, who ran more than any other player on the field as he pulled the strings for Leverkusen's win, deflected praise after the match.
"The team's performance was better than my own -- the team showed how well we can play football."
- Union 'close to perfect' -
American midfielder Brenden Aaronson picked up a second yellow 21 minutes in, with Union 1-0 ahead against the promoted side after an early Gosens strike.
Darmstadt equalised just three minutes later but the undermanned visitors fought back, Gosens and Kevin Behrens both scoring headers to give Union a 3-1 lead at halftime.
Visiting centre-back Danilho Doekhi added a fourth -- again with the head -- midway through the second half.
It was the first time Union have won their opening two matches of the season in the top division.
Gosens, who was starting for the first time after making the move from Inter Milan to the red side of Berlin in August, said "it comes pretty close to a perfect day."
"To score two goals in a 4-1 win away from home with a man down - it doesn't get much better than that."
Promoted minnows Heidenheim threw away a 2-0 lead to lose 3-2 at home against Hoffenheim, with Andrej Kramaric scoring an injury time penalty to win the game for the visitors.
Heidenheim's Jan-Niklas Beste missed a penalty just 16 minutes in, but atoned minutes later, curling in a free kick from an acute angle for the club's first ever top division goal.
Home forward Marvin Pieringer looked to have sealed the win with a goal midway through the second half, but Hoffenheim scored three times in the final 13 minutes.
Wind scored twice in Wolfsburg's 2-0 home win over Hoffenheim last weekend and has hit all of his side's goals this Bundesliga season.