Charlie Adam says Rangers could be in for a long season if they fail to get a result against Aberdeen on Saturday.
Steven Gerrard's men begin their Premiership campaign at Pittodrie as they aim to deny Celtic a historic tenth successive title.
Former Liverpool midfielder Adam made 88 appearances for the Ibrox club, but believes it's Celtic who are made up of "serial winners" going into the new season.
Speaking on BBC 5 Live Sport, Adam said: "They need to stop 10-in-a-row, it's as simple as that.
"That'll be the marker, and that's what Steven (Gerrard) will be telling the players, we need to start the season well.
"I just think Rangers need to come out of the blocks flying. If they don't, it's going to be a long season.
"Listen, Celtic are favourites. You can't write them off. They are serial winners. They've won for a number of years, the players they've got in their squad.
"It might just be that some of the players that Rangers have got need to step up to the mark this season and show that they've got that bottle to try and stop 10-in-a-row, because it will be huge if they don't."
