London - Arsene Wenger believes Arsenal's 5-1 demolition of West Ham proves they are mentally strong enough to cope with the pressure of battling to finish in the Premier League's top four.After error-strewn performances in successive defeats against Manchester City and Chelsea, Arsenal's season appeared to be in danger of imploding and Wenger reportedly held crisis talks with his players earlier this week.VIDEO: Arsenal v West Ham highlightsBut the Gunners temporarily silenced their critics with an emphatic victory at the Emirates Stadium on Wednesday which ended a troubling run of three games without a win and lifted them within four points of fourth placed Tottenham."We got a good response, I watched the Chelsea game again and felt in the second half we were good and we continued that here," Wenger said."In the first half we controlled it but West Ham were dangerous on set pieces and we got punished. In the second we played with great pace, had tremendous movement and created a lot of chances."I never felt the players didn't know how important these matches were. I was just worried they were a bit inhibited in the big games."They have fantastic mentality and ability. That is what we want to show until the end of the season."Although Arsenal recovered from a 10-point deficit to finish in the top four last season, Wenger had conceded the team's position was beginning to concern him.And when Jack Collison fired West Ham into a shock lead in the 18th minute, it appeared the north Londoners were set to hit a new low.But, at the moment of maximum stress, Arsenal, so often accused of lacking character, finally showed some guts to equalise four minutes later through Lukas Podolski's fine strike.Olivier Giroud put Arsenal ahead with a close-range finish from a corner in the 47th minute and that was the first of four goals in 10 minutes as the Hammers were blown away.Santi Cazorla got the third with a sublime flick and Theo Walcott added the fourth before Giroud sealed the victory with a clinical strike, leaving Wenger to salute his players' attitude."At 1-0 down if you concede the second goal it can go the other way. The Premier League is like that. You are in trouble as soon as you are not at your best," he said."I thought it was an interesting test at that moment. It was vital to equalise before half-time."When Lukas Podolski is in that form then he is very important. He can finish and give assists, he is a team player."Wenger also revealed Belgian defender Thomas Vermaelen is likely to miss Saturday's FA Cup fourth round tie at Brighton with an ankle injury, but he doesn't expect the Arsenal captain to be sidelined for long."Vermaelen was kicked and he twisted his ankle. He is a doubt for Saturday, but it is nothing major," Wenger added.For West Ham manager Sam Allardyce, the defeat became secondary to his concern over the health of young defender Daniel Potts, who was taken to hospital after being knocked unconscious following a clash of heads with Arsenal's Bacary Sagna in the second half."Danny has gone straight to hospital with a concussion. He couldn't give the correct answers to the questions the doctor asked."It was a clash of heads. I think that knocked him unconscious and then he hit the floor a dead weight so it was a double blow."You are concerned about the time it took to get him treated, but they have to make sure they get him on the stretcher the right way to protect the spine."We think he will be ok. Hopefully there is no more damage to the neck or the spine."