Inter Milan boss Claudio Ranieri admits he only needs one striker for his system.

Diego Milito and Giampaolo Pazzini are in direct battle for a starting place.

"If I continue with the new system, then they will always be alternated, because we need only one striker. Playing every three days means everyone can play and keep fit. I am happy with what Mauro Zarate is giving to the side, but I'm also convinced he can give much more," said Ranieri.

"The fact remains we're running out of time. Enough walking, it's time to start running. I can see the team has broken out of its shell and we are getting back on track with the right approach, but Siena are a truly tough opponent on their home turf.

"We've got to take it one game at a time."