Granit Xhaka praised his side's "pure mentality" as Florian Wirtz's goal in the 11th minute of stoppage time snatched a 3-2 win for reigning champions Bayer Leverkusen at Borussia Moenchengladbach in Friday's Bundesliga opener.

Leverkusen were cruising at half-time, after a Xhaka stunner and a Wirtz goal gave Xabi Alonso's side a two-goal lead.

With rain teeming down at Gladbach's Borussia Park, Nico Elvedi brought the hosts closer with a 59th-minute strike before newcomer Tim Kleindienst levelled the scores with five minutes remaining.

A second-half delay when home supporters set off flares in the stands meant a lengthy period of added time. In the 10th minute of that stoppage time, Ko Itakura clipped Amine Adli's boot in the box, bringing Wirtz to the spot.

Wirtz's effort was saved but the Germany midfielder hammered the ball in on the rebound as his side won late again.

Leverkusen built a reputation for saving matches with last-gasp goals during their incredible run last season and Friday's strike was officially the latest goal in league history.

"We started well in the first half and were dominant. We said at half-time we don't want to let them back into it," Xhaka told DAZN.

"They came back but again we showed our pure mentality and we can take the three points back to Leverkusen from a difficult away match."

Leverkusen coach Alonso was at a loss for words.

"I have no explanation for that. It's football. It's happened for us a lot."

Wirtz, 21, said he was "glad" to be given the responsibility of the spot-kick, saying he "wanted to decide the game".

"I know that at the end it was a bit lucky, but I don't want to complain. We're happy that we won at the end.

"We made it a bit hard for ourselves. There's plenty of things we need to keep working on but we can be happy we got the three points today."

- Defending champions -

Fresh off an unbeaten league and cup double last campaign, Leverkusen picked up another piece of silverware last Saturday by beating Stuttgart on penalties to lift the German Supercup.

Gladbach, a fallen giant who narrowly avoided relegation last season, were dealt a blow shortly before kick-off, with star midfielder Manu Kone left out of the squad due to an impending move away from the club.

Leverkusen midfielder Xhaka blew the lid off the game early, rocketing in a brilliant long-range effort after 13 minutes, giving Gladbach goalie Jonas Omlin no chance.

The effort was a mirror image of the Switzerland captain's goal in Leverkusen's 1-0 German Cup final win over Kaiserslautern in May.

Xhaka, who spent four years at Gladbach before his move to Arsenal, held his hands in the air, refusing to celebrate the stunner against his former club.

A bleach-blonde Wirtz doubled Leverkusen's lead after 38 minutes, blasting in on the turn in a crowded penalty area.

Kleindienst looked to have pulled one back for the hosts just before half-time but the former Heidenheim forward's effort was struck off on VAR review.

Gladbach's Elvedi, who lost possession just before Xhaka's opener, redeemed himself for the hosts, heading in a rebound to cut Leverkusen's lead 14 minutes into the second-half.

Kleindienst then levelled things up late, pushing past some sloppy defending from Edmond Tapsoba to blast the ball into the net.

In the final minute of stoppage time, Adli went down in the box and a VAR review brought Wirtz to the spot.

Omlin kept the low shot out but Wirtz was first to the rebound, knocking it home to ensure his side started their title defence with three points.

Friday's league opener, which features the defending champions, was the first without Bayern Munich since 2013.