By Alex Stevens

Sergio Romero and Marcos Rojo are the hardest players at Manchester United, according to Chris Smalling.

The Argentine duo are considered by the England international to be tougher than skipper Wayne Rooney, who did boxing training as a child and considered the sport as a career before choosing football.

In an interview with Sky , the England defender lifted the lid on life at United behind the scenes.

Asked who is the hardest United player, Smalling said: “Sergio (Romero) and Marcos (Rojo). They’ve got that Argentinian switch on them, they’re not all there.

“If something bad was to happen, you want them in your group. Wazza got knocked out by Phil Bardsley so that lowered his reputation a little.”

A video was released last year that appears to show Rooney being knocked out cold by his former team-mate Phil Bardsley in a sparring session in the United player’s kitchen.

In the video, the two former team-mates pull on boxing gloves and trade blows as they spar in Rooney’s Cheshire mansion.

Full-back Bardsley then catches Rooney square in the face with a left jab, sending the United captain plummeting to the floor. Rooney lays prostrate and the video comes to an abrupt end.