The Nerazzurri slumped to a 3-1 defeat to Siena on Sunday, and the Colombia midfielder has called on his side to give their all in the hunt for a Champions League berth
Andrea Stramaccioni's side were comfortably beaten 3-1 on Sunday and had Christian Chivu sent off in the second half, allowing AC Milan to leapfrog them into fourth place following their 2-1 win over Udinese.
"We are working hard, but the consistency in our results just isn't there. This was an important match today but we didn't win," he told Sky Sport Italia.
"We’re working hard and doing well in training, but we need to apply it in the game. We can’t give up. We’re still in it and we have to continue to fight.
"My preferred role is in the middle of a three-man midfield, but I’m getting along very well in the spot with which Stramaccioni has entrusted me.
"I know I can give more. Today wasn't one of my best days, but I’m positive about the next match."
In spite of his disappointment on a collective and personal level, Guarin admitted that their opponents were worthy winners on the balance of play.
"Siena deserved their victory. We came up against a team who were prepared and always on the attack. Then with Chivu’s red card everything became more difficult," he told Inter Channel.
"Now we have to put this ugly defeat behind us and look forward. Every one of us has to give more."