Mata believes winning the FIFA Club World Cup will provide a massive boost for them to start mounting a fightback on their return.
"It will be perfect," he said. "We know that December is a crucial month for English teams.
"We are playing a lot of games in the Premier League and are now in Japan but if we win this trophy it will be a big step forward for the rest of the season.
"Once we are back from Asia we have to keep winning games in the Premier League. And let's not forget that we are alive in the rest of the competitions too - FA Cup, Capital One Cup and Europa League. The club have never won this one and we will try to add it to our trophy cabinet."