GINO van Kessel had a debut to remember as the new signing scored a stunning goal to help fire Oxford United to a victory against Portsmouth which sent Pep Clotet's men top of the fledgling Sky Bet League One table.

A tight game was opened up just after the break when Wes Thomas pounced on a mistake by Portsmouth goalkeeper Luke McGee.

The visitors were still well in the game, which got better as the afternoon progressed.

But United continued to make the clearer chances and van Kessel made the most of his opportunity just three minutes into his maiden appearance in English football.

Josh Ruffels struck in stoppage-time to cap off a fantastic second half.

It ensured United made it two wins out of two in Sky Bet League One, bouncing back superbly from their midweek Carabao Cup disappointment against Cheltenham Town.

The pre-match news revealed a serious knee injury to Ivo Pekalski, but another of United’s overseas recruits was handed a debut.

Ricardinho was one of five changes from Tuesday night.

His start at left back allowed Marvin Johnson to play his more natural role further forward, but the Brazilian made an inauspicious start with a foul throw early on.

Aside from a Brett Pitman header which flew wide, there was little else of consequence in the opening stages.

Both sets of supporters contributed to a terrific atmosphere, which may have contributed to a frenetic contest played at 100 miles per hour.

The only save of note in the first half-hour was from a 20-yard Kyle Bennett effort which goalkeeper Simon Eastwood turned round the far post for a corner.

United saw plenty of the ball, but found Pompey a tough nut to crack.

It took a surge forward from Ryan Ledson in the 30th minute to disrupt the visitors’ back four, but his square pass for Thomas in the area was scrambled clear.

The game gradually began to open up late in the half.

Eastwood saved a header from Jack Whatmough after his central defensive colleague Christian Burgess had nodded a deep corner across goal.

United’s clearest chance of the half also came from a set piece.

When a corner was cleared out to Ricardinho, the full back’s sliced shot fell for Mike Williamson. The centre back’s Cruyff turn and shot dragged the ball for Curtis Nelson to stab wide.

Despite the U’s skipper’s protests, referee Graham Salisbury awarded a goal kick.

The official’s whistle came to the hosts’ rescue three minutes before the break, chalking off Pitman’s header into the net for a push on Williamson.

Deadlock was broken two minutes in the second half, thanks chiefly to an error from McGee.

A neat move by United created space for Christian Ribeiro to cross from the right. The Pompey goalkeeper got two hands on the ball but spilled it for Thomas to bundle the ball into the net from close range.

  • Wes Thomas scores the opening goal after Pompey keeper Luke McGee's error 

The first substitution of the afternoon came for the men in black, with Salisbury not fit to continue and replaced by fourth official Marc Wilson.

Thomas’s goal led to a far more entertaining game, as Pompey were forced to be more adventurous, giving a confident United space to attack.

The contest entertainingly see-sawed from end-to-end and Pompey had several shouts for a penalty waved away.

At the other end, one terrific cross-field pass from Johnson picked out an unmarked James Henry on the edge of the box, but after collecting the ball he could only prod a lob over under pressure.

McGee partially made amends for his error on the goal by tipping over a venomous effort from substitute Jon Obika after good work by Johnson.

Rob Hall fizzed a shot wide as United built up a head of steam, but it was United’s third substitute who stole the show.

Van Kessel had only been on the pitch for three minutes before making the game safe.

The loan signing from Slavia Prague appeared to have made a mess of a chance when he failed to control a square pass cleanly.

But instead he managed to beat one man in the box, before sharply cutting past another defender and ramming a low shot into the net.

He wheeled away in celebration and although there was still almost ten minutes remaining, the stuffing had been knocked out of Pompey.

Ruffels rubbed salt in the wounds in stoppage-time with a cool finish for his second goal of the season.

Oxford Utd (4-4-1-1): Eastwood, Ribeiro, Nelson, Williamson, Ricardinho, Henry (Hall 76), Ledson, Ruffels, Johnson (van Kessel 79), Payne, Thomas (Obika 69).

Unused subs: Shearer, Martin, Carroll, Rothwell.

Booked: None.

Portsmouth (4-2-3-1): McGee, Talbot (Baker 69), Burgess, Whatmough, Haunstrup, May, Rose, Evans, Naismith (Chaplin 56), Bennett, Pitman.

Unused subs: Bass, Davies, Main, Kabamba, Close.

Booked: None.

Referee: Graham Salisbury (Lancashire).

Attendance: 9,510 (1,810 visitors).