YORK City manager Gary Mills says his high-flying team will have to be at their best to extend their own unbeaten run in 2012.

The Minstermen haven't tasted defeat in seven games in league and cup.

But their Grimsby Town opponents tomorrow are 13 unbeaten in the league and have lost just one of their last 21 matches to top the Blue Square Bet Premier form guide.

Despite a difficult task ahead in Cleethorpes, at a ground where they haven't won in 12 visits stretching back almost 38 years, Mills is looking forward to the big game.

He said: "It's a tough game but a fantastic one to look forward to.

"If you want to be winners, you have to go and beat the best teams and, at this moment in time, Grimsby's form is better than anybody else.

"But I know we can go there and beat them."

If York are to complete a league double over the Mariners, they will need to do something they haven't achieved since November 1987 and that's score at Blundell Park.

It's a five-game sequence that Mills' team will have a better chance of doing if 15-goal top-scorer Jason Walker plays after his recent injury.

The former Luton forward has missed the last eight games due to a groin injury but could start tomorrow after netting a stunner in the first meeting at Bootham Crescent.

Mills added: "Jason Walker is looking good and I've been really pleased with him.

"The weather situation has not been ideal for him but he played 45 minutes at Middlesbrough and he's trained really well.

"He has certainly put himself in contention for tomorrow's game."

Another man who could be involved is new loan defender Ben Gibson who joined from Middlesbrough this week.

The 19-year-old is highly-rated and Mills believes he will prove a good addition after fending off competition from a top-flight Scottish club for his services until the end of the season.

With David McGurk (knee) and Jamal Fyfield (ankle) out injured, Gibson will come into consideration for a centre-back place at Blundell Park.

Mills added: "He's a good, young player, who has a hunger for the game and, despite his age, is already a man.

"I like his attitude. He's a good talker for a young player and his desire is fantastic.

"His signing makes us stronger defensively and gives us more competition for places."

Former Fleetwood midfielder Scott Brown sits out the final match of a three-game ban after the Trophy tie against Ebbsfleet was postponed and misses the trip across the Humber Bridge.