The striker struck a hat-trick last week in victory at Bologna.
"I am very happy. The hat-trick against Bologna meant a lot to me and then the Nazionale call arrived," he told Milan Channel.
"I had a small problem, as my knee was a little swollen and I had to rest for a few days, but I have recovered and am now fine.
"Milan must always aim to win and we need to be consistent to achieve great results. On Saturday we're facing Atalanta and have to give 100 per cent.
"If I score another goal, then of course that'll be even better, but the important thing is that we get the three points."