STUART Parnaby has vowed to put previous disappointments behind him as he seeks to make his mark on the Middlesbrough first team.

The 22-year-old was initially promoted to the senior ranks in October 2002 and, after making his league debut in a 2-2 draw with Leeds, the Durham-born defender went on to make 20 more appearances for the Teessiders either side of Christmas.

England Under-21 honours followed but, after suffering a series of niggling injuries, Parnaby gradually found himself pushed back into the reserves.

He was restricted to 13 senior displays last term - a tally that looked unlikely to be beaten this year following the summer signing of Dutch international Michael Reiziger.

But, with Reiziger nursing a shoulder problem that will keep him out for at least another month, Parnaby has been handed a golden opportunity to make the right-back berth his own.

Things didn't go to plan the last time that happened but, after starting every game bar one this season, he is determined to prove difficult to dislodge.

"I've got to take my chance and make an impression," said Parnaby, who has featured in central defence and midfield in the past. "We don't know how long Michael is going to be out for.

"I was 19 when I first got into the side and that was a really good chance. I had a nightmare with injuries, but there's nothing you can do about that.

"I've got to learn that you've got to look after yourself. Hopefully I can stay injury-free and keep my run in the team going.

"I know what I'm capable of. I played first-team football when I was even younger so I knew I could do it then. I had a run of 20-odd games two years ago and that proved I could do it."

Parnaby is still learning the art of being a full-back and, in Saturday's 1-0 defeat to Chelsea, he found himself lining up against one of the Premiership's most highly-rated wingers.

Damien Duff has outfoxed far more seasoned defenders than Parnaby in the past and, while the youngster admits he struggled to keep tabs on the Irish international in the second half, he is confident he will learn from the experience.

"Duff was a big outlet for them," admitted Parnaby. ""He's certainly the best out-and-out winger I've faced. There's not many of them about like him. A lot of left-siders seem to be right footed now.

"For an out-and-out winger, he's about as tough a test as you're going to get. I thought I did alright against him in the first half, but he came into it a bit more after the interval."

The next stage of Parnaby's learning curve will come in the Czech Republic on Thursday night as Boro play the second leg of their UEFA Cup first round tie against Banik Ostrava.

Steve McClaren's side have the cushion of a 3-0 lead after the opening leg on Teesside but, while there will be an inevitable temptation to sit back, too defensive an outlook could create its own problems.

"We can't afford to let them come onto us and dictate the play," said Parnaby. "We've got to play with the same tempo we showed in the first leg.

"They played on the counter-attack over here and that's how we've got to play over there. The atmosphere's going to be hostile, but we're expecting that."

Read more about Middlesbrough here.