THE only thing that makes Celtic look vulnerable at the moment is the date.

Predictably brushing Dundee United aside at Parkhead last night extended their form to nine wins in their last 10 matches and it opened up a 12-point lead at the top of the Clydesdale Bank Premier League. Fans chanted "bring on the Juve" because there is respect rather than trepidation about soon facing Juventus in the last 16 of the Champions League.

But the date? That can make Celtic feel vulnerable, the prey rather than the predators. Neil Lennon is confident Gary Hooper will still be his player when the transfer window closes at the end of the month, but the fuss being created about the forward, heightened by the frequency of his goals, means the issue is a distracting nuisance for the club.

Hooper will not leave without their blessing and nor is there the impression that he is in any rush to go. But even so, a club is made to feel nervous when it has an irresistible asset and the manager of Manchester United comes to watch. Sir Alex Ferguson saw Hooper score two of the four goals which sunk United – his 21st and 22nd of the season – in a performance which did nothing to dilute his newsworthiness. Supporters sang his name and the sponsors gave him the man of the match award. A contract offer, as lucrative as the club is able to offer, has been rejected. There is the clear sense he is in or around the departure lounge. Fans will have to share Lennon's faith that he has four more months and a few more goals in him for Celtic.

Hooper was always going to score last night, of course. He had an early blur of chances. One shot went wide, a header went over the bar, another effort hit the woodwork albeit after the whistle had sounded. If he was advertising his talents it was as if he feared the potential buyers might leave the ground early.

By the 19th minute he had his inevitable goal. Celtic were defending a corner when they stole possession and swept upfield. Lassad showed awareness and intelligence to allow Georgios Samaras and Hooper to fan out to either side of him bepore playing the ball to Samaras on the left. United were hopelessly exposed and, when Samaras played it back across the box, Hooper's finish was routine.

It would be an exaggeration to say that all eyes were on Hooper. Plenty were scouring their other forwards too, contemplating who they might rely on if he leaves. Samaras? Lassad? It would be between those two unless any new signings are made, given that Miku is out of the picture and Anthony Stokes, lacking fitness, must first work his way back off the bench and into the team. He came on in the dying minutes to make his first competitive appearance since August.

Parkhead was more anxious than normal when Samaras was hurt in a challenge with Keith Watson just before half-time. Samaras, star of a Head & Shoulders television commercial in Greece, looked a bit roughed up but recovered to play on after treatment.

Lassad isn't quite there yet as a Celtic forward but he does show real promise. A goal last weekend, and some bright play here, added to a sense that the Tunisian could grow into a bigger role if the club has to live without Hooper. His all-round game is better now than Hooper's was when he first came to Glasgow.

There must always be a smattering of goals from other parts of the team, too, and two of the back four joined with a defensive midfielder to double Celtic's lead. Charlie Mulgrew played a short corner to Mikael Lustig, whose long, deep cross was met by an superb downward header by Wanyama. That was from the training ground. He almost converted another header but instead struck the post, followed by Hooper and Lassad efforts within the next couple of frantic seconds as United threatened to unravel.

The visitors could not live with Celtic. Gary Mackay-Steven – no eye-catching tricks this time – fluffed an early chance went Johnny Russell put him clear through on Lukasz Zaluska and barely registered on the game after that. Nor did Russell deliver a demonstration of the abilities which may make him a potential target for Celtic or anyone else. United had to do too much defending for there to be any consistent supply to their forward players, Russell, Mackay-Steven and Jon Daly. The couple of chances that came Russell's way went unconverted.

All the menace was at the other end of the pitch. Lassad and Samaras opened up United again and a low cross to the front post was flicked home expertly by Hooper 10 minutes from time. Soon he made another one, being closed down by defenders but feeding the ball wide to Scott Brown, who curled a finish beyond Radoslaw Cierzniak and inside the far post.

United were undone. Defeats at Parkhead are explicable: the last time they won here was in 1992. But, now, any time United are meek it will generate calls for Peter Houston, the manager who intends to leave in the summer, to go sooner rather than later.