Celtic have lost to Motherwell and Ross County but still lead the way by 15 points ahead of the visit of Aberdeen on Saturday.
Manager Neil Lennon questioned whether some players were thinking more of a summer move than the task in hand when they threw away a two-goal lead in Dingwall on Saturday.
But Forster is confident they will get back on track against the Dons as they look to secure the title win and prepare for their William Hill Scottish Cup semi-final against Dundee United on April 14.
"We want to wrap the league up as quickly as possible so we´re all 100 per cent focused on the job," he told the Celtic View.
"We can´t be complacent, though. We have to go out and keep trying - a lot hasn't changed in the league, we still have to go out and perform well.
"A few times we´ve had a gap at the top of the table and it hasn't meant we´ve dipped in form so hopefully that doesn't start happening now.
"We all want to win the Scottish Cup, especially after the disappointment of losing the League Cup semi-final, so it´s vital we get to the final this time.
"It´s important we´re fully focused because we know it will be a tough game against Dundee United when it comes around.
"We´re going for the double so we´re still very motivated."
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- Dundee United