Georgios Samaras is looking for Celtic to keep in touch with Rangers ahead of their January 3 meeting at Parkhead after Sunday's defeat at Hearts left them trailing their Old Firm rivals by four points.
The Hoops' lunchtime win over Motherwell last week took them five points clear before Rangers reduced the deficit with a win over St Johnstone later in the day and followed it up by taking another three points at Dundee United in their game in hand in midweek.
The Ibrox men thrashed Motherwell 6-1 on Saturday to put pressure on Tony Mowbray's side but it was thought that Celtic, on the back of a four-game winning run in the SPL, would respond in positive fashion against a side who could have gone bottom of the table on Boxing Day if they had lost.
However, despite Samaras giving the visitors the lead with his 10th goal of the season, Jambos captain Michael Stewart levelled from the spot after Celtic skipper Gary Caldwell was sent off for felling Jamie Mole in the box.
And in the 76th minute Ismael Bouzid headed a David Templeton cross past Artur Boruc to leave the visitors stunned.
Celtic play Hamilton on Boxing Day then face a trip to Kilmarnock before the visit of Rangers and Samaras wants the Parkhead men to be in striking distance by then.
He said: "You can't talk about the gap, there are so many games still to go. The Old Firm game is two weeks away, it is not the right time to speak about this. But of course we have to be close to them, within one win so everything can change.
"But you never know what is going to happen week-to-week. We were disappointed to lose to Hearts but we made lots of chances and have to take the positives. We've found our form in the last six or seven weeks and we have created a lot of chances and scored goals.
"We are hopefully going to continue like this in the next weeks and hopefully months, and I think we will have the strength to go to the end. Celtic and Rangers are always in the race to win the title and I'm happy that this season there are more teams pushing, like Hibernian, Hearts and Dundee United.
"Lets's see who has the quality to last to the end.''
Bouzid, who accepted manager Csaba Laszlo's decision to immediately replace him after he scored the goal due to the "unnecessary'' yellow card he had picked up minutes earlier for gesturing to the Celtic fans, praised the assist of Templeton for his first goal in maroon since arriving at Tynecastle in the summer following a short spell with the Turkish club Ankaragucu.
He said: "It was my first goal for Hearts, I usually only score one or two a season. I was up for the corner and I just waited, I saw David take the ball and I scored from the perfect delivery.''