West Ham will have to make do with competing on just the two fronts for the remainder of this season after Southampton advanced to the FA Cup quarter-finals at their expense. A trip to Seville in the Europa League next week and their tilt for a top-four berth in the Premier League will no doubt soften the disappointment of defeat here but there will be a lingering frustration for David Moyes given how his side allowed a game in their grasp to get away from them. Romain Perraud rocked West Ham with a phenomenal, rasping strike from outside the box – it was some way to his open his account for the club – before the former Southampton loanee Michail Antonio levelled in the second half. But James Ward-Prowse restored the hosts’ advantage with a no-nonsense penalty before the substitute Armando Broja secured passage into the next round, wriggling clear of three defenders before slotting home into the far corner. It was a minor miracle that Southampton were not trailing when Perraud rifled a shot into the top corner beyond the West Ham goalkeeper Alphonse Areola, one of two changes made by David Moyes. His opposite number, Ralph Hasenhüttl, elected to make sweeping changes, the captain Ward-Prowse and Kyle Walker-Peters the only players to keep their place from Friday’s comfortable victory over Norwich. Southampton, perhaps unsurprisingly then, looked awkward and were haphazard until Walker-Peters shifted the ball from right to left on 31 minutes. Perraud took one touch to move the ball out of his feet before dispatching a left-footed effort that flew in from 25 yards, whistling diagonally across Areola. Hasenhüttl could not hide his delight, running on to the pitch in celebration, and the Southampton substitutes stood to applaud. Two of those on the bench, Stuart Armstrong and Armando Broja, arrived for the second half. They could have doubled their advantage before the break but Adam Armstrong played a hospital pass to Will Smallbone, who tentatively joined the attack to the striker’s right. In the away technical area Moyes, arms folded, could be forgiven for wondering how his team were behind. Pablo Fornals, again operating from left wing-back, telegraphed a fine pass over the top of the Southampton back line to give Jarrod Bowen a sight of goal within the opening 67 seconds but the defender Jack Stephens nicked the ball away to prevent the forward a shot at goal. Fornals was causing problems, slipping in Antonio only for Stephens to get again avert the danger after Yan Valery was lured into tracking Manuel Lanzini who rushed towards the ball. Ben Johnson roamed forward from right-back and rattled a shot against the side netting after going close following more good work by Fornals. The West Ham wing-back cut inside Perraud but Moussa Djenepo, who endured a difficult first half, got back in time to poke the ball out for a corner. Djenepo was replaced at the interval, along with Shane Long, who was grounded with a back injury. But West Ham’s best first-half opening came when the powerful Michail Antonio, who won the Football League Trophy with Southampton in 2010, stood up a cross from the left, after Soucek and Fornals combined. Bowen rose in the six-yard box but could not direct his header on target. Soucek was forced off early in the second half after taking a stray elbow to the head from Ibrahima Diallo. West Ham did not allow the break in play to disrupt them and they replied when Willy Caballero made a mess of a Bowen corner. The ball flew towards Kurt Zouma at the near post and Caballero failed to gather, allowing Issa Diop to pick up the pieces and hook the ball towards Antonio, who prodded in from close range to spark delirium among the almost 5,000-strong travelling support in the Northam Stand. But five minutes later West Ham were at the mercy of the video assistant referee, Simon Hooper, who advised the referee, Andre Marriner, to take a closer look at how Craig Dawson had prevented Broja from getting a clean shot at goal. Broja raced on to Stephens’ quick free-kick and Dawson was adjudged, after Marriner went to the VAR monitor, to have fouled the striker. Ward-Prowse slammed the subsequent penalty down the middle to give Southampton, semi-finalists last season, a whiff of another run deep in the competition before Broja sealed victory in stoppage time.