Greg Halford believes he has now addressed a significant weakness in his game.
The Pompey star has had spells in the top flight with Reading, Sunderland and Wolves but failed to claim a regular starting place at any of those clubs.
After falling down the pecking order at Wolves, he was allowed out on loan to Fratton Park last season where he impressed, before signing a permanent deal in the summer.
But Halford believes he could have remained in the Premier League had he ironed out the minor lapses in concentration that have occasionally blighted his game in the past.
And after recognising the fault, he insists he will continue to work on it in a bid to improve himself as a player.
Halford said: ‘Earlier on in my career and the downfall of why I didn’t stay in the Premier League for a longer period of time was my concentration was a problem.
‘I just used to switch off at times.
‘Some would say things would become a bit too easy for me.
‘But then I would get sloppy and make mistakes.
‘I’ve tried rectifying that a little bit and as a centre-back, maybe 90-per-cent of it is all about concentration and nothing else.’
And while the former Colchester man is relishing his return to right-back, he believes his stint in central defence has helped his focus.
He said: ‘Sometimes it was comfortable playing at centre-back and I wasn’t pushed physically and mentally.
‘I felt that I lost a bit of fitness playing there.
‘But it’s taught me a good lesson and going back to right-back, I don’t think I make as many mistakes and we don’t concede as many goals.’