Thomas Mueller rescued Germany with a late winner as the hosts came from behind to earn a nervous 2-1 win over Romania in Friday's World Cup qualifier to open a six point lead at the top of their group.

Romania took a shock ninth-minute lead in Hamburg when Rangers winger IanisHagi ghosted through the defence and fired past Germany goalkeeper Marc-Andre terStegen, a late replacement for injured Manuel Neuer.

The Romanians led 1-0 at the break, however Serge Gnabry equalised with his 20th goal in 30 internationals after 52 minutes.

Mueller then came off the bench for his 107th Germany appearance to claim his 40th international goal nine minutes from time.

"It was annoying to concede the early goal, but the team fought, never gave up and played with confidence," said Germany head coach Hansi Flick.

"In the end, the win is more than deserved as we dominated for long stretches."

The result extends Germany's lead at the top of Group J ahead of Monday's next qualifier away to North Macedonia. A win in Skopje would put the Germans on the brink of punching their World Cup ticket.

"The earlier we qualify, the better. Today was a big step. Now we want to make it clear on Monday," said goal-scorer Gnabry.

After a shock defeat to North Macedonia in March, Germany got their World Cup qualifier campaign back on track with wins over Liechtenstein, Armenia and Iceland in September under Flick.

This was a far less confident performance from the Germans who were rattled by falling behind early on, yet Flick enjoyed his fourth straight win.

The Germans were denied a penalty by the VAR after slight contact on Timo Werner, just before Hagi stunned the hosts.

The Rangers forward got the better of Chelsea defender Antonio Ruediger and swept the ball past the diving Ter Stegen.

There were nervous glances in the German ranks, similar to those in March when North Macedonia earned a shock 2-1 win in Duisburg - the first time Germany had lost a World Cup qualifier for 20 years.

Gnabry, Marco Reus and Werner all had chances for Germany, but the hosts took a long time to recover from falling behind.

The hosts pulled level when Gnabry drilled in his shot seven minutes after the break.

Werner and Reus made way for Mueller and Kai Havertz with 20 minutes to go. That turned the game.

Havertz squandered a golden chance when he got in behind the defence with the ball at his feet, before Mueller fired the winner into the roof of the net after Leon Goretzka's header.

Romania could have grabbed a late equaliser when their captain Vlad Chiriches fired just wide of the German goal.