The Hammers have had a great start to life back in the Premier League, picking up 14 points from their first eight games, which made yesterday's showing in the 2-1 loss at the DW Stadium such a shock for Allardyce.
Although there will be plenty of chances to bounce back, West Ham's run of fixtures up until Boxing Day looks very challenging, with Manchester City, Tottenham, Manchester United, Chelsea, Liverpool, Everton and Arsenal all coming up.
Allardyce said: "When you look at the fixtures we've got coming now, this was a chance for us to get a result.
"The group of games now, you know anything other than your very best is going to be a problem to get a result, and even your very best might not get you one.
"We had a really good performance against Arsenal and got beaten 3-1. Slipping up here and everyone saying, 'Well, it's a good start', you've got to minimise your slip-ups as much as possible. We were never at the races, Wigan deserved the win."
West Ham were undone early in each half, with Ivan Ramis' stunning volley giving Wigan an eighth-minute lead and James McArthur making it two in the 47th minute before James Tomkins struck in injury time for the visitors.
It was defender Ramis' second goal for the Latics and second against West Ham after he also scored in the Capital One Cup last month, a fact particularly galling for Allardyce because he tried to sign him in the summer.
The Hammers boss said of the Spaniard's goal: "This one was even better. There was a foul on (Winston) Reid but the referee was looking at the ball coming over.
"Ramis pushed into Reid, which gave him that little bit of room, but the technique on the volley, you'd be raving about it if it was (Robin) van Persie. We did try to get him but I think Roberto tipped us because he's Spanish."
Ramis arrived at Wigan from Real Mallorca in August, and Latics boss Roberto Martinez is delighted with the way he has settled into the team.
"He was captain of Mallorca for a few seasons, he attracted the attention of many teams and we were pleased he chose to come to Wigan," said Martinez. "We had to make a massive effort to get him.
"He's the sort of player you want to sign to try to improve every season, he came at the best moment of his career and you can see his leadership skills are getting stronger.
"We were very pleased when we signed him but we're really looking forward to seeing Ivan Ramis at his full potential because he's a tremendous defender."
Saturday's victory was Wigan's first at home this season, ending a run of six Premier League games without a win, and the three points put some daylight between them and the bottom three.
Martinez felt it was just reward for the near misses they have had at the DW Stadium this season, and he said: "More than a relief, there was a real excitement.
"I do feel in the performances at home we've been very close. We played really well in certain games.
"Against Everton we dropped two points in the 87th minute because of the penalty, against Stoke we were twice ahead, and that was just a period of getting us as strong as we can and adapting to things that we changed this season.
"I was very pleased we had time to prepare for this game. The two international breaks, I know they distract everyone but for us they are a disaster.
"Now we can concentrate on a very good block of games until March. This performance is a combination of the good work in all the games where we didn't get the results."