Celtic defender Mikael Lustig believes Rangers need to "find a new way to play" if they are to beat their rivals on Sunday.

The Hoops remain undefeated in Old Firm derbies since Brendan Rodgers arrived in Glasgow in the summer of 2016.

Swedish international Lustig said while Rangers have marginally improved over the past season they must find a new strategy if they wish to leave the Scottish Cup semi-final victorious.

Lustig said: "Rangers have been a little bit stronger and they've tried to bring new players in to make them a better team, so, of course it seems like they have taken a small step to being better.

"But they probably need to find a new way to play or do something different, we'll see what they do."

Rodgers' side remain on course to complete back-to-back trebles, with the League Cup already secured and a twelve-point advantage in the Premiership.

Despite failing to hit the same heights as last seasons "Invincibles", Lustig still fancies his side's chances of repeating the feat.

He added: "You just look at what we done in the league and in Europe and the fact we've already won the League Cup so we should be favourites, absolutely.

"We feel good, the last couple of times that we've been in at Hampden we played really good football and we won so we're looking forward to it.

"We know that we will be big favourites."

Lustig insists the possibility of a record back to back treble victory is an enticing one.

He said: "Last season was so good for us, for the players and the fans. Whether we would be able to do that again was going to be really hard.

"I've been here for all six years and of course every season you want to win the treble. To have the chance to do it two years in a row is incredible."

"We're always humble and do our talking on the pitch. We've done it so far, and hopefully we can do it again."