The 21-year-old Argentine has impressed in his five starts for the Owls, forcing former England goalkeeper Chris Kirkland to watch from the sidelines, but his loan expires on January 1.
Martinez had his most impressive ‘game’ to date in Wednesday night’s abandoned match against Wigan Athletic at Hillsborough.
In monsoon conditions, and a boggy pitch, Wigan sliced through the home defence only to find Martinez in inspired form before the game was called off after 59 minutes.
“I love Wednesday. I really want to stay here and extend my contract,” said Martinez.
“I spoke to Arsenal and I said I will not be going back to the club as first choice so I need to play.
“I want to give my team clean sheets and that is what all goalkeepers want.
“I was giving everything in training and then I got a chance to play in the first team and show every game that I can be the No 1.
“I want this club to get out of the relegation zone. I know we can do it because we have good players and we are working hard for it.”
Martinez came to Hillsborough on the advice of former assistant manager Terry Burton, now Arsenal coach, and the goalkeeper revealed he had been warned he would face a battle to dislodge Kirkland.
Not that the former Wigan player offers anything but assistance on the training ground.
“We talk every day and train together,” said Martinez. “Chris encourages me to be ready, be sharp.
“He made me a cup of tea at half time to help me keep warm.
“He’s a real professional on and off the pitch. I train every day with the ’keepers; if you had a bad relationship, it would be really hard.
“If Chris was playing, I would wish him luck as well.
“He is an amazing goalkeeper. Terry Burton told me Chris is really good, I would be on the bench and would have to play really well to get in. I think I have done that.
“The club gave me my chance and I think I am showing in every game I can be Sheffield Wednesday’s No 1.”
The Argentine has made just two first-team appearances for the Gunners, the second in their 7-5 League Cup win over Reading last season.
But after taking over the gloves for the derby defeat to Huddersfield Town and Dave Jones’s last game in charge at Blackpool, Martinez has featured in a mini revival which has brought two wins in three and the Owls’ first clean sheet of the season.
Martinez – who had a brief loan spell at Oxford United last year – has clearly impressed caretaker-manager Stuart Gray.
“I think he showed on Wednesday night after they got through our back four and we’d given away possession far too easily, he made some good saves, even in those conditions,” said Gray.
“Nothing beats playing, He can go to Arsenal, train Monday to Friday, then he’s unfortunately not getting games. Players want to train all week then get a game at three o’clock on a Saturday.
“Credit to him, He’s enjoying it, getting good experience. Although I’d rather him not be as busy as he was on Wednesday.
“Even he found the conditions difficult. He’s one of the best kickers I’ve seen for a goalkeeper, but he had trouble with his kicking – he couldn’t get the ball off the ground. So in the end we were saying ‘don’t throw it down on the floor, kick it straight out of your hands’.
“I’m pleased that he wants to stay, That’s down to Arsenal as well.”
Martinez could not be in better hands, under goalkeeping coach Andy Rhodes and training alongside Kirkland.
And the former Liverpool goalkeeper was praised by Gray for his professional attitude since he was surprisingly dropped from the first team last month.
“I have to give credit to Chris Kirkland as well,” said Gray. “He’s obviously disappointed he’s not in the team, but he’s such a top professional.
“He’s given Emmi lots of advice. He’s got Andy Rhodes working with him as well, an experienced goalkeeping coach, but Chris has played a big part as well, encouraging him.
“Emmi’s got the shirt and he’s got to keep hold of it. He’s getting good experience. He’s probably missed that match sharpness. He’s getting better.
“You want competition in every position. Chris probably lost that competition when Stephen Bywater left. We brought Emmi and it created that competition.
“It’s the same, for example, at left-back; if Reda Johnson doesn’t pull his weight, Joe Mattock will be in. At the moment we have far too many players in the treatment room. We’ve just lost that bit of competition to keep people on their toes, where they think ‘if I don’t perform, I’ll be left out because someone is ready to grab the shirt’.
“We never expected to lose three centre-halves, and Lewis Buxton has been out with hamstring and groin problems; Reda has been out with his foot (injury) – that’s been the disappointing thing, neither Dave Jones nor I has had a settled back four.”
Victory today – or even a draw – could see Wednesday climb out of the bottom three and cut the gap on teams like today’s opponents, Bournemouth.
“The period we’re in now, people will be looking over their shoulders, thinking Sheffield Wednesday just took six points out of a possible nine; that’s what the pressure is on the players – once we get out of the bottom three we want to move up the table,” said Gray, who has been given the festive period to stake his claim for the manager’s job on a permanent basis.
“Probably the Bournemouths, the Charltons are thinking ‘Barnsley and Sheffield Wednesday are down there, we’ve got a bit of space’. Suddenly that space has got very close.
“We have a home game against Bournemouth and I’ll be preparing the team to win. If we don’t, we don’t get beaten, and if the results go our way we still get out of the bottom three.”