Newcastle United boss Sam Allardyce has challenged Obafemi Martins to grab his chance today against Liverpool.

Big Sam said: "Oba has been disappointed recently and, like most players, he wants to play every week.

"That is something you have to deal with, having strikers competing for the top places. Mark Viduka being fit is a key element for us at this stage.

"The combination of Michael, Mark and Oba - I've been waiting to see if they can gel on a regular basis. But, as it has gone up to now, it's difficult to keep any pair together.

"Oba can get the job done. We know he can score a goal, we know he is a big threat with his pace and I am sure he likes the big games."