Southampton fullback Ryan Bertrand admits playing at centre-half will be tough against Sunderland ace Jermain Defoe.

Bertrand is ready to step in for injured captain Virgil van Dijk in the middle to help Saints avoid being dragged into the Premier League relegation scrap.

He said: “Playing in the middle comes naturally. It's the same defensive principles, but there are different requirements of the job.

“There is no more running forwards as much and there's a bit more discipline. It's a bit more of a high risk position."

On Defoe, Bertrand adds: “Class is permanent and he's arguably one of the best in the league at what he does.

“He's come back and he's playing – with all due respect – in a lesser side, according to the table at least, but still producing the goals."