Oxford United came safely through their FA Cup test at the Kassam Stadium to take their place in tomorrow's first-round draw.

Mark Creighton thumped in a left-footed volley early in the second half when Thurrock failed to clear a corner, and that dispelled any anxiety they had against the in-form Blue Square South side, who had fancied their chances of causing a shock.

And an own goal by substitute Lee Flynn, after good work by Sam Deering, sealed their passage.

The U's also hit the woodwork three times, through Adam Murray, Jamie Cook and Deering.

Mark Creighton settled Oxford United's anxiety by firing them in front with a thumping left-foot volley eight minutes into the second half.

They had hit the woodwork twice before then, both attempts striking the outside of a post.

Chris Wilder brought in Jack Midson, up front, and Adam Chapman, into midfield, to replace the suspended James Constable and Matt Green.

Murray operated on the right side of United's attack, though he soon interchanged with Jamie Cook and switched flanks, while Chapman was employed in midfield.

Thurrock took the game to united at the start, forcing the first two corners and pegging the home side back in their own area for a spell.

But it wasn't long before Wilder's men got on top with some fine poassing moves.

The in-form Blue Square South side looked a far more compact and cohesive unit than their very near-neighbours Grays, who play in the same division as Oxford, and they had an attacking menace about them.

Fola Orilonishe's early inswinging corner gave Ryan Clarke problems, and a few minutes later, when striker David Bryant pulled the ball back from the bye-line, it needed a vital clearance from Luke Foster from in front of the goalline, to stop Leon McKenzie pouncing to score.

Cook cut in from the right to hit a low drive, which the keeper got behind, and not long after he stumbled when darting in on goal.

And on 16 minutes, they almost broke through when a slick move ended with Adam Murray cleverly letting the ball run across him before striking a left-foot shot, which slammed against the left post.

Midson, taking on the responsibility of leading the line, had a mixed afternoon, sometimes holding the ball up well, other times losing possession, but often it wouldn't quite drop for him.

When Steve Kinniburgh threaded a beautiful pass through, Midson just couldn't reach it.

Foster put a couple of headers wide at corners, and Chapman saw a long-range free-kick shot deflect into the keeper's arms.

Deering replaced Chapman for the second half, taking over as an orthodox right winger to stretch opponents who would surely tire as the match wore on.

And, sure enough, attacking towards their fans in the Oxford Mail Stand, United started to dominate.

Cook jinked past two defenders inside the area and shot against the post, as he seemed almost to want to walk the ball in.

But from the corner, which the visitors couldn't clear, Creighton hammered home a volley from 12 yards which left keeper Joe Woolley rooted to his spot.

As further chances came, Midson headed wide and Deering headed against the right post from Kinniburgh's fine cross.

Some of the Thurrock players were by now treading water as Oxford's superior fitness began to tell.

And when Deering centred from the right, Flynn turned the ball into his own goal as Midson put him under pressure.

Midson himself had a late goal ruled out by offside, but it was comfortable in the end.

Danny Bulman, the only United outfield player yet to score this season, really should have opened his account on 90 minutes when he went through with just the keeper to beat, but he shot wide.

Oxford Utd: Clarke, Batt, Foster, Creighton, Kinniburgh, Bulman, Chapman (Deering h-t), Clist, Murray, Midson, Cook (Sandwith 81). Subs not used: Turley, Kelly, Day, Perry, Rhodes. Booked: none.

Referee: Amy Rayner (Leics).

Att: 3,296 (100 from Thurrock)