OXFORD United crashed out of the Emirates FA Cup at the first hurdle on a shocking night where Port Vale fully deserved to progress.

The Sky Bet League Two strugglers did everything expected of an underdog, raising their game and getting into the faces of the higher-ranked visitors.

And when chances came their way, an energised Vale took them as the errors piled up for a lethargic United side.

A mistake from Simon Eastwood led to Gavin Gunning heading the opening goal on 16 minutes.

The visitors had plenty of the ball but were ponderous and rarely stretched a Vale side who doubled their lead through Tom Pope’s header early in the second half.

United were ultimately fortunate to avoid a heavier defeat, but there was no disguising a dreadful night.

Pep Clotet was true to his pre-match assertion he would be taking the competition seriously.

He made just one change from the League One defeat at Fleetwood Town, with Mike Williamson replacing the rested Curtis Nelson.

The visitors forged the first chance of the night, but Vale goalkeeper Ryan Boot smothered James Henry’s effort after he had been put through by Ryan Ledson.

United had most of the ball, but the home side were fired-up and carried a threat when they fired crosses into the box.

Pope was the focal point and only a terrific save from Eastwood turned a glanced header from the experienced striker round the post on the 15-minute mark.

United’s goalkeeper came to claim the resulting corner, but his quick throw only found James Gibbons. The right back steadied himself to cross for Gunning to head powerfully into the net.

It was a dreadful goal to give away and only encouraged Vale to increase their intensity.

United were hassled all over the pitch and struggled to turn their possession into a goal threat.

They certainly did not create anything as clear as the opening which fell too easily to Marcus Harness midway through the half.

The midfielder got into the box, but Eastwood stood firm to make a vital save which kept the visitors in touch.

United’s No 1 also had to save from Gunning, who got up to win a clean header from a corner on the half-hour mark.

Wes Thomas was anonymous until he went down holding his mouth in the 40th minute after a foot race with Gunning.

Referee Mark Heywood saw nothing wrong and the striker was clearly still fuming when he collected a booking for an overly-aggressive aerial challenge on Antony Kay a minute later.

Williamson was forced off with a knee problem at half-time, replaced by Aaron Martin.

The interval had little impact on the flow of the game, as United’s patient passing was overwhelmed by Vale’s industry.

A mix-up between Martin and Eastwood led to a panicked clearance, but within eight minutes of the restart the size of United’s task had doubled.

Pope had already served notice of his aerial threat, yet despite being outnumbered in the six-yard box he managed to meet Danny Pugh’s cross with a firm header which bounced into the net.

Rob Hall and Joe Rothwell were summoned from the substitutes’ bench, but their introduction made little impact.

Vale continued to look by far the most dangerous side and should have increased their lead midway through the half.

Dwight Tiendalli’s careless backpass played in Tyler Denton, who somehow steered the ball wide with only Eastwood to beat.

Eastwood also had to make a smart save to deny Anton Forrester from scoring just after coming on.

It prevented a heavier defeat, but there was no doubt over which side was cruising through to round two.

Port Vale (4-2-3-1): Boot, Gibbons, Anderson, Smith, Gunning, Pugh, Kay, Worrall (Forrester 77), Harness (Turner 84), Denton, Pope.

Unused subs: Hornby, Tonge, Montano, Stobbs, Reeves.

Booked: Harness, Denton.

Oxford Utd (4-2-3-1): Eastwood, Ribeiro, Williamson (Martin HT), Mousinho, Tiendalli, Ledson, Ruffels (Rothwell 62), Henry, Payne, Mowatt (Hall 55), Thomas.

Unused subs: Shearer, Carroll, Xemi, Obika.

Booked: Thomas, Martin.

Referee: Mark Heywood (West Yorkshire).

Attendance: 3,443 (396 visitors).