And while the Senegalese striker has yet to make the impact he would have hoped for following his summer move from the Reebok Stadium, Keane has faith that he will prove a good long-term signing.

Diouf was excellent in pre-season and started the campaign in the first 11 but has subsequently become a peripheral figure – not that his manager is reading too much into that.

He said: "Dioufy has a great mentality and great ability to go with it.

"He hasn't featured much in the first team recently but he has shown the right attitude on the training pitch when it comes to getting back in the side.

"He'll be disappointed that he hasn't made the impact so far that he would have hoped for. But there's still a long way to go yet and players do take time to settle in.

"I think that's what happened with Dioufy although I wouldn't make too much of that personally.

"You look at players like Teemu Tainio for example or Pascal Chimbonda and they were players who came in and who also started the season in the first team but for one reason or another have not featured too much recently.

"It's an understandable thing when players come to a club that they take time to settle.

"And it has always been the case at every club that different players go through different experiences. Some settle straight away, others take time and some settle early on but then have a dip in form.

"The fact is though that we've brought quality players to the club and they'll be here for some time to come.

"So it is early days for players like Dioufy, and I'm sure it won't be long before we start seeing the best of him."

Wanderers boss Gary Megson described Diouf as 'mad' this week – in what was meant as an affectionate description, and while Keane did not quite go that far, he could see what his opposite number was driving at in talking about one of the game's more colourful characters.

"If you want to be in top football, you've got to have a lot of different aspects about your character," said the Sunderland manager.

"I wouldn't go so far as to say he is mad – although I would say we are all mad in different ways – but he's a bubbly character and he has a passion about his football.

"He looks to stay behind and work on his game and that's what we like to see at the club."