Sam Allardyce said his West Ham United team must improve their away form if they are to enjoy a comfortable second half to the Barclays Premier League season.

The Hammers' travel sickness continued as they slumped to a 3-0 defeat at Sunderland on Saturday - their sixth defeat in ten away league games in 2012/13.

Sebastian Larsson climaxed a dominant opening from the Black Cats by lashing the hosts in front on 12 minutes. West Ham kept their deficit to one goal until half-time, despite losing James Collins to a calf injury, only for a 47th-minute defensive mix-up to allow Adam Johnson to double Sunderland's lead. With the Hammers chasing the game, James McClean added a third.

Speaking to West Ham TV, Big Sam said his players had simply not produced the goods on the road again at the Stadium of Light.

"It was the time and the way that we conceded the second goal that was most frustrating. We had a free-kick and a chance to score a goal to get us back in the game at 1-1, we had set up nicely and the ball went in with us having two defenders sat midway inside Sunderland's half without a Sunderland player anywhere near them.

"The ball gets headed out and, in the space of a few seconds, Stephane Sessegnon is running down their right in behind Guy Demel and he passed it across the box and there is James McClean stood all on his own. God only knows where our defenders had gone.

"Jussi Jaaskelainen gets us out of the mire by making a great save and then we go and mess up the clearance and Johnson puts it in. It probably summed our day up from start to finish. I don't know why the players have shown what they showed today because it wasn't anywhere near our best, as we know.

"They can play but it's away from home that is becoming a bit of a concern for me because of the lack of performances and goals we're getting. It's becoming a big concern for me and I have got to make sure I put it right for Wednesday because otherwise we'll be looking at a real thrashing at Old Trafford and that won't be good for confidence going into the home game with QPR next weekend.

"Our home form and performances are outstanding but our away performances are the reverse of that - they are just not good enough."

Just a few months on from a promotion season that saw West Ham win a club record-high 14 away league matches, the Hammers have managed just two victories and five goals in ten away league matches.

Big Sam was also concerned at the drop-off in performance compared to that produced in the 2-2 FA Cup with Budweiser third-round draw with Manchester United at the Boleyn Ground the previous weekend.

"We didn't look like the same set of players this week who played last week, with no disrespect to Sunderland because they are not as good as Manchester United, and managed to close Manchester United down and nearly shut them out.

"We couldn't shut Sunderland out today - in fact we let them do what they wanted, attack when they wanted and play to their strengths when they wanted. Whenever they attacked and got around our box they looked like they were going to score.

"We showed no organisation or desire to stop them doing what they wanted to do, and we did all of that perfectly well against Manchester United, so it baffles me that the application to stop the opposition playing at home and to get the fans excited wasn't there.

"On the back of that, we're unlikely to go and win a game. We've got to win the right to play and stop the opposition when we're playing on their patch and then we can look to play from there on. We never did that today at all."

While West Ham remain eleventh in the table, Big Sam called on his squad to collect points as quickly as possible to avoid being dragged into a relegation battle.

"We have a game in-hand but it's Arsenal away and we're not playing very well away from home at the moment."

Having already lost Mark Noble to a slight calf injury in the lead-up to the game, Big Sam was forced to reshuffle his defence when Collins was forced off with a more serious calf problem midway through the first half.

With George McCartney and Joey O'Brien also on the sidelines, the manager said he aimed to delve into the transfer market again this week to bolster his defence.

"Losing James is a massive blow. With Joey not here and George out with a long-standing medial knee ligament injury, to lose Ginge to a tear in his calf leaves us threadbare defensively and I need to get somebody in as quickly as I can.

"We need either a centre-back or a left-back - at least one of them - by the time we play QPR. We have to look very carefully at who we play on Wednesday and then for the following Saturday.

"We have to take it on the chin and admit we were second-best today. We do lose games of football and we have to accept that we will lose, but I cannot accept how we played today when I saw how well we played seven days ago. "