Giovanni Reyna has again came off the bench to score a late winner for Borussia Dortmund, securing a 2-1 Bundesliga victory at Mainz.
Reyna - who scored Dortmund's late winner in a 4-3 win against Augsburg on Sunday - repeated the feat after coming on with just under half-an-hour remaining.
Fellow substitute Sebastien Haller flicked on a free kick for Reyna to sweep home in the third minute of added time.
Reyna's goal, his fourth of the season, keeps Dortmund's winning start to 2023 intact and moves them up to fifth, five points behind league leaders Bayern Munich.
"We're happy to come out of the starting blocks like that into the new year," Dortmund coach Edin Terzic said.
"We know we have a lot of work in front of us."
Lee Jae-Sung got Mainz off to a great start in the second minute, scoring with a header from a corner, but Dortmund levelled almost immediately through Julian Ryerson.
Union Berlin came from behind to beat Werder Bremen 2-1 away and move second, just three points behind Bayern, thanks to a goal in each half from Janik Haberer and Kevin Behrens.
Freiburg and Eintracht Frankfurt drew 1-1, with Freiburg's Matthias Ginter cancelling out the in-form Randal Kolo Muani's first-half strike for the visitors.
Bayer Leverkusen defeated Bochum 2-0 to leave the visitors in the relegation zone, while Mergim Berisha's late goal was enough for Augsburg to beat visiting Borussia Monchengladbach 1-0.