Irwin should know a thing or two about the position, having played there in the 1999 Champions League final, one of his 529 appearances in a 12-year stint with the Old Trafford outfit.
World's best: Dennis Irwin reckons Evra is a better left-back than Ashley Cole
And, whilst he accepts there is competition, particularly from Ashley Cole, Irwin has no doubt Evra is currently the best at his art.
'Patrice is the number one,' said Irwin. 'Ashley Cole has improved an awful lot this season. But Patrice has come on a lot too and this year has been his best.'
On the spot: Ex-Manchester United defender Dennis Irwin
In fact, so effective has Evra been, during a period when he was the only regular member of United's back four to remain injury-free, Irwin feels he edges Wayne Rooney as United's player of the season.
The Irishman admits the view is shaped partly by solidarity amongst the full-back fraternity. But Irwin does feel Evra's performances have been worthy of the highest praise.
'Wayne Rooney has been tremendous, particularly over the past three months,' said Irwin. 'But Patrice Evra has been every bit as good. He has been very consistent at a really high level.
'Regardless of what Wayne has done, Patrice has been our player of the season. Unfortunately for full-backs, centre-forwards get all the glory because they score goals.'
Not that it looked like being that way when Evra first arrived from Monaco for £5million four years ago. The 28-year-old struggled badly during his first few months in England, finding the sheer pace of the game virtually beyond him.
Wayne's World: Rooney laughs off Irwin's comments that Evra is having a better season than him
Slowly though, the adaptation process was completed, and now he is looking to maintain his record of winning the title in every full season he has spent with United.
'He came in a January, at the same time as Nemanja Vidic, and they both struggled,' recalled Irwin.
'The Premier League was totally different to the league he was playing in. It is a different culture, different weather, different everything.
'You have to get used to all that. But since that first couple of games he has come on leaps and bounds. 'He always looked good going forward but defensively Patrice has improved an awful lot.'
Evra will set his sights on beating Liverpool at Old Trafford on Sunday as United look to maintain their position at the top of the Premier League.
Meanwhile, in the rather less glamorous surroundings of Altrincham's Moss Lane, it is anticipated Owen Hargreaves will take the first steps on his comeback trail tonight.
Hargreaves pulled out of a planned first appearance in 18 months since surgery on both knees to cure a tendinitis problem last week, but Sir Alex Ferguson was more bullish when he spoke about the England international last Friday and it would be a disappointment if he was not involved against Burnley's second string.
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