Sam Allardyce rued a solitary defensive lapse that cost his side dear away to Southampton on Tuesday night.
While the npower Championship table may still show the Hammers in second spot, they are now five points adrift of the Saints, who made it 17 straight home victories with their 1-0 triumph in front of a biggest-ever St. Mary's crowd.
It came from a Jos Hooiveld header just before half-time, something Big Sam felt should have been avoided with his team's aerial capabilities.
"It was disappointing to lose our unbeaten away record but even more disappointing to lose it off a set-play," the manager said. "We didn't really do anything in the first half although still had some chances. We conceded a soft goal from a situation we practice regularly. We are one of the biggest sides in the league but that didn't stop us going one-nil down.
"We deserved something out of the game for our second-half performance. Unfortunately, our sharpshooting centre-forwards who were magnificent on Saturday didn't have their shooting boots or the heading ability to score today. At least we came back and showed something of what we are really like in the second half. We took the game to them, were creative and created chances."
Those chances were all spurned with John Carew, Kevin Nolan and Sam Baldock all unable to convert good opportunities. Carew might even have equalised in the few seconds between Hooiveld's goal and the half-time whistle while Nolan was perfectly placed late on when substitute Mark Noble's ball into the box was deflected on to a post, only for it to run behind rather than out to the waiting skipper.
Allardyce's plans were complicated by Matt Taylor's new calf injury in the first half, while he had travelled without James Tomkins (groin) and, for the second game running, Carlton Cole (knee). Abdoulaye Faye and Henri Lansbury came in, meanwhile, with Jack Collison dropping to the bench.
Joey O'Brien returned from his hamstring injury late in the proceedings but he and fellow sub Freddie Piquionne could not affect a positive change. Big Sam, regardless, was not making excuses.
"Injuries happen to players and squads throughout the season," he said. "You have to cope for it. The thing that was disappointing was that we could not maintain our clinical form from Saturday.
"Perhaps it wasn't our day and it is a big disappointment to lose to Southampton, to lose our away record and find out when we wake up that they are five points clear of us. On the balance of play we should have still only been two points behind them.
"We knew it would be a difficult game because they have the best home record in the league. They are a good team but we should have rescued a point."
Allardyce will take Wednesday - his 57th birthday - to take stock but is not expecting too much in the way of festivities. "I don't celebrate birthdays at all at my age," he said with a wry smile when asked. "I try to forget them."
Points not presents were more on his wish list and he was clear what defeat meant to his men as they look towards Monday's trip to Brighton & Hove Albion.. "It can take between eight and ten games to make up five points. That is how important it was not to lose but we have.
"At the end of the day, we cannot complain about the chances we have made at the best home record in this league. With our quality I would have expected us to score at least one or two.
"When we wanted it right at the most important time against someone in direct competition it hasn't happened. We are second but still have a lot of ground to catch up. We will try and do that as quickly as we can."