The Premier League leaders took 10 points from a possible 12 over Christmas and New Year to open up a seven-point gap between themselves and Manchester City.
"The team spirit is as high as I can remember since I came here [in December 2010]," he told MUTV.
'We have done tremendously well over the Christmas period and picked up some great results, only dropping points against Swansea - which was a game that we should have won in my opinion.
"We have done brilliantly and you can see that in the team spirit as well, people are happy and there's a good, friendly and funny atmosphere in the locker room. It's a joy coming into work at the moment.
"Training is not hard work during the Christmas period because we have so many games. We just come in and prepare for the next game and then we go again."