Mauro Zarate has pledged to "show what I can do" to West Ham boss Sam Allardyce after completing his loan move to QPR.

The 27-year-old West Ham forward has signed for Rangers until the end of the season, and goes straight into contention for Saturday's Premier League trip to Burnley.

Zarate had fallen down West Ham's pecking order behind Diafra Sakho, Enner Valencia and Andy Carroll, despite a bright start in east London after joining from Velez Sarsfield last summer.

West Ham boss Allardyce defended his decision to allow Zarate to leave on loan, saying the striker "wasn't good enough", but the former Lazio man hit back on completing terms with QPR.

"I am happy. I need this, I need to play and Queens Park Rangers have given me this chance to show what I can do," said Zarate.

"The Premier League is the best in the world at this moment.

"Does my style suit the Premier League? Maybe. We will see!

"When I met the manager he told me he wanted to sign me for Portsmouth before, but in that moment I went to Lazio. But now I am here and will play for him.

"I will try to do different things with the ball, some skills to make the difference for the team, for me and for the other players. I am fit and I hope I can be involved on Saturday."

Allardyce had explained that Zarate's limited appearances at West Ham came down solely to ability.

"He wasn't good enough," said Allardyce.

"When you look at what Mauro has achieved when he's played compared to what Valencia, Sakho and Carroll have achieved all-round, when you look at (the) game, how much he's contributed, how much he's given in the all-round game and what they've given and you've got that array of talent to choose from, then somebody's going to be unhappy."

Rangers boss Harry Redknapp is expected to continue to seek another loan recruit to his frontline in the January window, despite signing Zarate, who scored two goals in eight appearances for West Ham.

Redknapp will hope Zarate can boost QPR's goal threat alongside prolific striker Charlie Austin in the Loftus Road club's Premier League survival fight.

"We're really pleased to bring Mauro in. He's a good footballer, someone with great ability who can play as a number 10," said Redknapp.

"I first saw him when he was on loan at Birmingham quite a few years back and I actually tried to take him to Portsmouth back then.

"He's a more-than capable player, he's already shown that, and hopefully he can come in here and do well for us."

Redknapp looks to have missed out on signing Jermain Defoe once again, with Rangers restricted to loan recruits this month.

Toronto FC striker Defoe remains a target for a host of Premier League clubs, with the 32-year-old keen on a return to England.

The Canadian club are holding out for a full transfer to let Defoe leave however, ruling QPR out of the running.