James Constable's 21st goal of the season - or 24th if you count his hat-trick against Chester - brought United a second successive win which consolidated their place in the play-offs.

It was the very least Chris Wilder's team deserved after they dominated so much of the first half.

In the opening 30 minutes it was almost one-way traffic for the visitors, but they couldn't apply the finishing touch to some promising moves.

Yet once they got the goal, the confidence came flowing back, and so did their short-passing game as they moved the ball around the pitch beautifully, with their opponents often unable to get near it.

The goal came from a right-wing corner by Adam Chapman in the 53rd minute, as Constable escaped his marker to head home from ten yards.

Constable then had another powerful effort, from 16 yards, which keeper Stuart Coburn beat out.

Jack Midson headed against the bar in the first half and several other efforts went close.

Considering there was so little riding on the match, it was remarkable just how many Oxford fans had made the trip and the 360 following were basking in the sunshine behind one goal.

They saw most of the early action at their end, with the U's attacking that way, after Ryan Clarke got down low to save an 18-yard shot from midfielder Ryan Brown.

Sam Deering was seeing plenty of the ball, and from one raid he started, Damian Ball then got past his man on the other side and Franny Green almost converted his cross with a bicycle kick.

As the visitors continued to press, James Constable then saw two efforts inside the box well blocked by centre half Greg Young.

And Constable himself tried his luck with a scissors kick, from Franny Green's cross, with the same end result, as it bobbled wide.

This was a purple patch of good attacking play from the U's, which continued with Midson dummying for Adam Chapman to shoot, once more only a brave block denying them.

Midson had an effort ruled out for offside and there was a growing feeling that the visitors really needed to turn their superiority into a goal, or else they might pay for it.

Altrincham had a Peter Crouch-like 6ft 6in beanpole up front, in John McAliskey, who at times showed moments of surprising skill for such a big man, interspersed by other moments which fully explained why he was playing four divisions lower than Crouch.

Damian Batt tracked back well for a vital tackle on Colin Little when he ran on to a McAliskey flick-on.

But at the other end, Oxford were unfortunate not to take the lead. Chapman's corner was headed back by Mark Creighton, and Midson headed against the bar from four yards out.

Constable's goal early in the second half was the breakthrough they needed, and encouragingly, they didn't let up after that in the intensity of their play, working hard for each other, looking compact . . . looking like a team.

Matt Green replaced Midson just after the hour mark and nine minutes later, Lewis Chalmers came on for Franny Green, taking over on the right of midfield, with Chapmandropping deeper.

So solid had United been defensively, that it took Altrincham 71 minutes to test Clarke with a shot, substitute Chris Denham smashing an angled drive that the keeper saved high to his left.

The home side had a spell of possession late on and Clarke produced an excellent punch under pressure from Rob Williams to deny them what would have been a very harsh equaliser.

Oxford Utd: Clarke, Batt, Creighton, Wright, Tonkin, F Green (Chalmers 73), Bulman, Chapman, Deering (Sandwith 80), Midson (M Green 64), Constable. Subs not used: Turley, Day. Booked: Bulman.

Referee: Jake Collin (Merseyside).

Att: 1,356 (368 from Oxford).