Hansi Flick was pleased to see Niclas Fullkrug score on his Germany debut, but admitted his side were far from their best despite the 1-0 win over Oman.

The visitors struggled in Muscat in their World Cup warm-up game, relying on substitute Fullkrug's 80th-minute strike to take victory in a match that never really got going.

Though Germany will not be the only side battling fatigue amid a mid-season tournament, their lacklustre performance against relative minnows perhaps highlighted the difficulties they could face at Qatar 2022, which begins on Sunday.

Flick did take time to praise Fullkrug, the Werder Bremen striker winning his first cap after firing 10 goals in 14 Bundesliga games this season, while outlining his concerns over their warm-up showing.

"He deserved the goal," Flick told RTL after the win. "He had two or three other shots also. You could already feel when he was on the pitch, there was a presence up front."

Germany won just 38.4 per cent of their duels against Oman, but while the head coach admitted they will need to do better at the World Cup, did acknowledge that low number was likely down to his players wanting to avoid injury.

"Of course you have to say, if you see how we tackled in duels, that's not the level we want at the World Cup. But you can also understand that no one wants to hurt themselves."

Flick did lose defender Lukas Klostermann during the first half, with the RB Leipzig man only recently returning from a lay-off with knee ligament issues.

Germany kick off their World Cup campaign against Japan on November 23, before further Group E matches with Spain and Costa Rica.