Roy Keane believes the £75 million that Manchester United shelled out for Romelu Lukaku represents a "bargain". 

Lukaku arrived at Old Trafford from Everton in the summer and has scored ten goals in nine games for Jose Mourinho's side, helping them to second place in the Premier League and two wins from two in the Champions League. 

Lukaku's impressive numbers at this early stage have been helped by Manchester United's relatively tame early season schedule. All six sides they have met in the Premier League thus far are currently stationed in the bottom half of the table. 

Lukaku told RTÉ Sport last night that he was "relishing the challenge" and acknowledged that stiffer tests lie in wait.

Speaking on ITV Sport, Keane described the Belgian as a "bargain" at £75 million, though he added the proviso that he is keen to see Lukaku deliver against the bigger sides.  

"He is a good player at a good age. He knows the Premier League. He was a bargain at £75 million, it was obvious he was going to score goals.

"He has got off to a good start. He comes across well and seems like a decent character.

"His record at Everton was fantastic and clearly he has gone to a bigger club and better team, who will create so many chances for him, he will get 25-30 goals a season.

"The big test will be in the big games. For all top United strikers over the years, [it's] been scoring the big goals in the big games," Keane said.

"We are looking at these outstanding strikers all in great form but the time to judge them will be at the end of the season when the medals and trophies are being handed out.