John Hartson feels Celtic now realise that Rangers are ready to push them in the Scottish Premiership title race this season.
The Hoops are striving for eight domestic titles on the trot, with Rangers and Steven Gerrard aiming to dislodge them.
The Light Blues came from behind for a 2-1 win at Hearts on Sunday, despite finishing the Tynecastle clash with 10 men.
It means Rangers have claimed top spot in the table, one point clear of Celtic having played a game more, at this stage of a season for the first time since they re-emerged from liquidation.
Former Celtic goalscorer Hartson says Rangers credentials are crystal clear, though he expects Celtic will have the firepower to see them off.
“I think Celtic will appreciate that they are in a challenge for the title now,” the Welshman told the Evening Times.
“There are no medals handed out in December. There’s no prizes for sitting at the top of the league 14 games in.
“Celtic won’t be craning their neck to look over the fence. They’ll be wanting to simply go and win their own games and concentrate on what it is that they need to do.
“But I believe it is a genuine title challenge and I also believe that Celtic will be strong enough to prevail, and come out on top.”
Having retained the Betfred Cup on Sunday with a 1-0 Hampden Park win over Aberdeen, Hartson is tipping Celtic’s chances of a domestic ‘treble treble’ – though he warns nobody inside the Celtic Park dressing room will want to mention it just yet.
“The players won’t discuss it, the manager will bat it away at every turn and when you are in the team in a situation like that the last thing you really want to do is lose your focus by getting too carried away with yourself,” he added.
“But the fans will talk about it now. They want it, they’ll dream of it and from where I stand, I think Celtic can do it.”
Celtic are 1.30 to win at Motherwell on Wednesday. The Steelmen are 10.00 while the draw at Fir Park is 5.50.