The historic debut of the video assistant referee in Germany's top flight got a thumbs up from the relieved match referee after he spotted a penalty in Bayern Munich's opening win over Bayer Leverkusen.

Bayern were 2-0 up at home in Friday's first game of the new Bundesliga season when the VAR, which is being trialled for the first time in the German league this season, made its first intervention.

The controversial system came under the spotlight in the second-half in Munich when Leverkusen's Charles Aranguiz pulled Robert Lewandowski's shoulder to send the striker tumbling.

The match referee Tobias Stieler signalled -- outlining a television screen with his fingers -- that the incident should be reviewed by the video assistant referee, Jochen Drees, who was watching 575km (357 miles) away at the project's headquarters in Cologne.

Drees quickly confirmed the foul verbally to Stieler via a headset and Lewandowski slotted home the resulting penalty to seal Bayern's 3-1 win after Admir Mehmedi scored Leverkusen's consolation goal.

"I'm glad it worked so well, because what would have happened without the video assistant?" asked Stieler after the final whistle.

"I would have returned to the changing room to hear that I had missed an obvious penalty."

The VAR system made its senior international debut at June's Confederations Cup in Russia, but sparked controversy, receiving a mixed reception from fans after causing long delays and some confusion.

It is being further tested in the German league this season before world football's governing body FIFA decides whether to use it at next year's World Cup finals in Russia.

Behind the scenes, former FIFA referee Hellmut Krug, the German Football Association's (DFB) referee manager and VAR project manager in Germany, was clearly relieved.

"We are satisfied with the opening game," said Krug.

"Our intense preparations have paid off," he added after the technology behind the system was tested in the Bundesliga last season, but was not made available to referees in the relevant matches.

- System glitch -

The system got off to a bad start in Germany a fortnight ago, malfunctioning when Bayern beat Borussia Dortmund to win the German Super Cup -- the first time it was used for a top level match here -- but did not influence the result as Munich won 5-4 on penalties after a 2-2 draw.

And things did not go according to plan again when the Hawkeye system, which helps the VAR make offside decisions, failed to work in three Bundesliga matches on Saturday afternoon.

In contrast, the VAR's Bundesliga debut on Friday was a dream for German bosses - as it was a clear foul involving a high-profile player Lewandowski, the league's top scorer in 2015/16, and there was barely a delay.

"The communication between the referee and the video assistant was impeccable. They made a quick and precise decision when evaluating the relevant scenes," enthused Ansgar Schwenken, the German league's (DFL) director of football affairs.

"This first example of a video decision in the Bundesliga is sure to help the spectators, both at home and in the stadium, understand the decision which will help to accept this new innovation."

The VAR system was only used once on Saturday afternoon when VfB Stuttgart called for a penalty in their 2-0 defeat at Hertha Berlin, but replays showed striker Anastasios Donis was fouled outside the area.

Former DFB director of sport Matthias Sammer doubts the system will remove controversial decisions from the game.

"I think it was justified," said the ex-Germany midfielder of the Lewandowski penalty decision.

"My belly and my footballer's heart, however, tells me that there will be many standard situations in the future which will be discussed."

Source: AFP