Mikael Lustig believes Rangers will be wondering what they have to do to beat Celtic in the build-up to the Scottish Cup semi-final at Hampden on Sunday.

The Hoops are looking to extend their unbeaten run against their old rivals to 10 games as they aim for a second successive domestic treble.

Asked if that run could play on the minds of the Gers players, the Sweden international said: “Maybe a little bit. Obviously you need to find a new way to play or do something different and that cannot be good.

“But we will see what they do. We should be favourites, absolutely.”

On that theme, Lustig claims Rangers, 13 points behind the Premiership leaders, have taken only a “small step” towards closing the gap on the Parkhead side.

He said: “They have been struggling a bit and they have tried everything to take new players in and make them a better team, so of course it seems they have maybe taken a small step.

“Last season we were 30 points ahead of them and it is not that amount right now.

“If you look at it that way, they have maybe become a little bit closer, but we have the chance to win a treble. But we are still not really happy with the way we have been playing this season.

“We know we can do better. If we look to ourselves as well, we feel we can play better.”

Lustig also believes the 3-2 win over Rangers at Ibrox in the Premiership clash last month, when the visitors came back from behind twice and finished the game with 10 men, will give the Celtic players added confidence.

He said: “It is massive the way things happened in the game.

“They probably thought they had a really good chance to win it and we go down one man and still win. It is really good for us.

“Of course they haven’t won in a bit against us, so they probably saw the opportunity.”