WALES target man John Hartson has had his fair share of downs so you can forgive him if he sits back and laps up the current plaudits.

The burly 27-year-old is going through a purple patch in his football roller-coaster career and it wouldn't be a surprise if Alton Towers named a ride after him.

The Celtic star, like a fine wine, has matured into a player who has the world at his feet.

On the domestic front, he leads Celtic's front-line as they square up with arch-rivals Rangers in the Scottish Premier League and is an integral part of the club's assault on the UEFA Cup.

And he's not doing badly for Wales either. The striker is thrilled with the prospect of his country qualifying for a major championship final, but he's not becoming over-confident.

On the contrary, he's being realistic. "We all know there's a lot of hard work to go," said the 6ft, 34-times capped player.

Hartson's development as a consistent threat is paying massive dividends for both Celtic boss Martin O'Neill and Wales chief Mark Hughes.

"I have matured," he admitted. "I'm not getting involved in stupid things and I've managed to knuckle down. I can't pin-point why I've matured but we all get older, we all make mistakes when we're coming through.

"I always try my best and give 110 per cent. Sometimes I've gone over the top but that's only because I really care. If I didn't care I wouldn't be the player I am.

"I had a row with Martin O'Neill and that's only because I didn't want to be substituted.

People do get the wrong impression of me but it's something you have to live with, being in the public eye."

Looking back on previous experiences, Hartson said: "I've been relegated with Coventry City and Wimbledon and battled against it at West Ham. I've failed medical tests with clubs. Before that I played in the Cup Winners' Cup final with Arsenal - and now I'm back up the top of the tree again.

"Sometimes you have to go through the low points. They say you've got to get your fingers burnt to appreciate the finer things in life - and I have. I don't fancy going back to those dark days."

Hartson has settled at Celtic Park, partnering Henrik Larsson in a formidable attack which has helped the Old Firm giants to a UEFA Cup semi-final clash with Portuguese side Boavista.

And the Swansea-born player revealed: "I was unsure before the start of the season whether I could cut it at European level but I've really proved to myself I can.

"I've scored some important goals in Europe this season. The goal at Celta Vigo was the first time Celtic have qualified for Europe for twenty years.

"Last week's goal at Liverpool, my boyhood team, was great too. And I've found playing in Europe helps me when I play with Wales."