By Mark Meadows, dpa
Mitchell Weiser levelled just two minutes later with a very similar goal for eighth-placed Bremen, who won all four games in all competitions in December.
But Xavi again showed what the Red Bulls have missed in his absence when he drove forward alone on 35 minutes and saw his powerful effort deflected into the roof of the net for his first Leipzig brace.
“It was fun and it’s nice to be back,” he told DAZN. “It was my first injury in my life and I always thought about coming back strongly with the team and leaving an impression.”
Coach Marco Rose praised the “difference maker” for a “quite extraordinary” comeback as left back David Raum also returned from injury and new right back Ridle Baku made his debut.
Benjamin Šeško let fly from distance early in the second half to make the game safe and Christoph Baumgartner added the late gloss before Oliver Burke’s consolation.
The win sent Leipzig back up to fourth, two points above Mainz, who had beaten bottom side Bochum 2-0 on Saturday. In Sunday’s late game, last term’s runners-up VfB Stuttgart moved up to seventh with a 1-0 win at Augsburg thanks to the returning Deniz Undav.
Rare midweek programme
Bayern Munich top the table by four points from champions Bayer Leverkusen. The Bavarians won 1-0 at Borussia Mönchengladbach on Saturday and Leverkusen beat Borussia Dortmund 3-2 away on Friday as the Bundesliga returned from a mini mid-season break.
The German top flight now has a rare midweek programme as it reaches the mid-point of the campaign, with Stuttgart hosting Leipzig on Wednesday in one of the stand-out clashes.
Without Xavi, Leipzig endured a terrible November before two wins in December and a 5-1 defeat at leaders Bayern Munich.
The Red Bulls have also lost all six games in the Champions League to be eliminated ahead of the final two league matches this month.
Klopp, who also attended French second division leaders Paris FC’s win over Amiens on Saturday, stunned football purists with his decision to join the Red Bull empire.
In addition to Leipzig, Klopp is responsible for clubs in Salzburg, New York, Brazil and Japan. The energy drinks company also holds stakes in Leeds United and Paris and is a financial backer of Torino and Atlético Madrid.