Wayne Rooney is still England's 'key player' - Slovenia's Jan Oblak

Slovenia goalkeeper Jan Oblak has defended under-fire Wayne Rooney by claiming he is still England's main threat.

Rooney has been struggling for form for club and country, having been dropped to the bench at Manchester United, while he was booed during England's 2-0 victory over Malta on Saturday.

Atletico Madrid keeper Oblak, however, believes Slovenia will have to be wary of Rooney when they face England on Tuesday if they are to emerge with a result.

"Rooney is a worldwide star and he is always very important for England's game. He is the key player we must stop," Oblak is quoted as saying by the Daily Mirror.

"While I don't fear any of the England players, they now have an enormous level in attack. That is their best line on the pitch at this moment in time."

Slovenia have picked up four points from their opening two World Cup qualifiers in Group F, drawing 2-2 with Lithuania last month and beating Slovakia 1-0 on Saturday.

"This match against England is very important for us, even though it is only in the third round of matches for our group," Oblak added.

"We failed in Lithuania and, after the match against Slovakia, it is necessary to beat England if we want to maintain our hopes of qualifying for Russia in 2018.

"England is a tough rival to play against even at home and there will be a lot of pressure on us. But we need to get a result, so we need maximum concentration as a main requirement on Tuesday.

"How can Slovenia beat England? We need to put them under pressure and make it a total battle from the first moment. We need to make them uncomfortable on the pitch, so I don't expect a match of beauty.

"England will arrive here with a new coach but with very similar players to the Euros in France, and they are always a tricky team to play against."