Celtic face Kilmarnock tonight trailing SPFL leaders Aberdeen by four points.
A defeat at Dundee United, draw with Ross County and the postponement of the New Year fixture at Partick Thistle coupled with a seven-match winning run for Aberdeen has put the pressure on Ronny Deila's side.
A double from Adam Rooney away to Motherwell yesterday added more substance to the challenge from Aberdeen reinforcing the view that Celtic face a real test in their bid to win the title for the fourth season running.
Under Neil Lennon Celtic were well in command of the title race by the new year with the current league table coming as a shock to the system of supporters unaccustomed to a title challenge since the liquidation of Rangers.
Deila appeared to survive an early storm that included two Champions League ko's and league defeats from Inverness Caley Thistle and Hamilton Accies but he now finds his side under the spotlight.
Anything less than a win on the artificial surface at Kilmarnock will intensify the pressure on Celtic who fly to Gran Canaria tomorrow for friendlies against PSV Eindhoven and Sparta Prague while Aberdeen get on with domestic business away to St Mirren on Saturday.
Deila won't take any risks with the fitness of Anthony Stokes, Mikael Lustig, Jason Denayer or Charlie Mulgrew tonight but insists that he has no issue with the surface at Rugby Park.
"I have a lot of experience with artificial pitches, so, for me, it's normal, but I know it's different for the players because they haven't done it so much," the Celtic boss said. "I think it's much better to play on a good artificial pitch than a poor grass pitch.
After going top of the SPFL in November Celtic's march towards the title seemed secure but doubts remain among many supporters about the direction the club is moving in.
With a League Cup semi-final against Rangers on February 1 followed by Europa League ties against Inter Milan next month was shaping as a pivotal month for Deila's reign.
Aberdeen's unexpected surge to the top of the table has put greater focus on Celtic's failings with the January league fixtures against Kilmarnock, Hamilton, Motherwell and Ross County taking on a greater significance.