The Reds are seven points clear at the Barclays Premier League summit but nobody at Old Trafford is getting carried away after Manchester City overtook the Reds from further back late into the 2011/2012 race to take the title.
"Over the years, December has been a good month for us," the boss told MUTV. "There's 17 games left and we have a seven-point lead. It's not what I would say is a healthy lead but it is a lead and it gives us something to kick on with.
"We just don't want to make the mistakes we did last year."
The manner of the success at the DW Stadium, scene of a costly reverse last term, clearly pleased Sir Alex.
"It's a very good result here," he enthused. "If you look at their home record, they're a very difficult team to play against. I thought it was a slow start to the game and we took a bit of time to get going but, once we started to get those corner-kicks, with Robin [van Persie] whipping them in, it was keeping them under pressure.
"After getting the first goal, the good thing about the team is they chased a second one immediately. 2-0 at half time was a good scoreline for us. There were one or two bits and pieces towards the end of the game but you have got to give credit to Wigan.
"They keep going and have got a bit of energy and guts about them.
"But the final two goals, particularly Robin's, were terrific football and it was a really good