Rafael Benitez formally unveiled Javier Mascherano as a Liverpool player last night and said his team will benefit directly from the five months of frustration endured by the Argentinian at West Ham. He believes his club have inherited a player toughened by his nightmarish spell at Upton Park.

Mascherano, who will make his debut against Sheffield United at Anfield this afternoon, said he is anxious to repay the faith shown in his ability by Benitez, but concedes he does have a point to prove in the Premiership having failed to make a mark at West Ham. Indeed he has featured in only six hours and 33 minutes of competitive action this season, and only 235 minutes in the league, with his team yet to score a goal in any of the games he has played in.

"I hope what happened to him at West Ham will help him here at Liverpool," said Benitez. "I've spoken with him many, many times about his problems down there. As soon as I heard that he and Carlos (Tevez) had signed, I knew it would be difficult for them both because it's a different style of football. It's hard if you don't speak English and you are not used to the style or the culture. But Javier was learning there, even if he wasn't always playing, and he will continue to learn here.

"He has had six months to acclimatise to life over here and to the Premiership and he'll be a bit more used to things now. We pursued him because we knew that he would be a good option for us and not very expensive. He's 22 and has 22 caps: how many players in England have that many caps, and for such a big country as Argentina, at that age?"

Mascherano, who has joined on an 18-month deal with an option to extend it, has not played at all since early December, having failed to hold down a place at West Ham under either Alan Pardew or Alan Curbishley.

"It was hard, but, when things are going well, people are happy to accept the praise, so it works the other way as well," he said. "I have to take some responsibility for why it didn't work out. I clearly wasn't playing well enough to feature in the team, and the backroom staff obviously didn't think I was worth it.

"There were times when I thought I may have to move on, but I'd always been ambitious to play in Europe and you only learn from the bad times you have in life. I just kept my head down and working hard in training. I'm on a learning curve and I've never regretted what's happened. It has helped me to develop as a person. But it's important to feel wanted. That Rafa and the people here at Liverpool have kept an eye on me despite the fact that I've not been playing is great. Rafa was quite concerned that my career was going nowhere and I intend to repay him for keeping his faith in me."

Liverpool will hope there are comparisons to be drawn with the initial difficulties of Robert Pires and Emmanuel Petit in England. The former was nondescript in his first season at Arsenal before carrying all before him in his second and Petit, signed from Monaco in 1997, admitted to Arsene Wenger six months into his first season that he feared he was not up to Premiership football. He ended that season a title winner.

"I don't have any doubts about Javier's quality or his mentality," Benitez said. "He may not be very tall, but he's a strong boy and I don't think the Premiership would be a surprise for him now. After six months of training every day at West Ham, he knows the difference between football in Brazil and the Premiership and he's a player with enough quality and experience to do well over here." ... Guardian Service