CELTIC legend Frank McGarvey has warned Celtic must beat Aberdeen on Saturday - or risk seeing their hopes of four-in-a-row unravel.

The Hoops are back in SPFL Premiership action at the weekend coming off four straight games without a win, a feat they have managed just four times in 10 outings in all competitions this term.

That run has left Ronny Deila's men out of the Champions League and languishing fifth in the Scottish top flight, while a defeat to Derek McInnes' side could see Celtic slip nine points behind current leaders Inverness, albeit with a game in hand.

McGarvey said: "To try and gel the team in the next three months will be Ronny Deila's main objective as well as getting his team settled.

"At the start of the season I thought Celtic were a certainty to win the Premiership but now I'm more unsure.

"For the first time since Rangers went out the top flight I have a doubt that they might not win it with this team. I've not thought that before.

"The team under Neil Lennon at the start of the season were certainties to win it. Now I'm looking at the players and questioning if they can score goals as well as keep them out.

"It's important for any Celtic team to win their next game as if they don't they are under pressure right away. But with the poor start they've had to the season, they really have to win this game."

Despite scoring nine goals in their first two Premiership games, Celtic have only bagged two more in the four matches since.

Hoops boss Deila has sought to rectify that problem by bringing in strikers Stefan Scepovic and John Guidetti. And while McGarvey believes both appear good acquisitions, he has called on more familiar faces to up their game.

"It's a team that's together now, and the forwards aren't really sharp," he said. "It's very, very difficult to gel a team, no matter who you are, and get them playing well.

"The manager has a big rebuilding job to do with the players he has. It's not the best league in the world at the moment, but even Celtic are struggling in it now. They didn't manage to beat Dundee, and if anything Dundee should have won.

"Ronny Deila deserves his chance, I don't have a problem with him. The players he has brought in should be good enough to win the league.

"It's uncharted waters for this team and Ronny will hope these new guys can score goals and do well.

"I think some of the players who have been at Celtic Park for a while have not performed to the same level - Charlie Mulgrew for example, who has been excellent for the club in previous years, but I think his form has dipped a bit.

"It's okay saying Celtic have good players, but they've not gelled. That needs to happen over a period of time. That's my main concern."