Luke Shaw said he has learnt the lessons of last year and has not turned up for preseason training unfit again this time around after taking a fitness coach on holiday with him.
The left-back joined Manchester United for £27 million in 2014 but was criticised by manager Louis van Gaal before he had made a competitive appearance for being out of shape.
And the England international has admitted Van Gaal was right to find fault as he revealed he and Adnan Januzaj paid for a trainer to join them on a break in Dubai in a bid to ensure they were in the right condition.
"I only had myself to blame," Shaw told the Manchester Evening News. "I didn't arrive at the club in the correct shape and things didn't go to plan. The manager told me his feelings and I totally accepted that.
"At a massive club like United you have to be at your best. But I learnt and this season I feel much fitter, much sharper and I have the experience of a year at Manchester United behind me. The big difference is my fitness.
"There were stories that Adnan and I were ordered to take a trainer but they weren't true. We decided to ask a member of the coaching staff to come with us and we paid his flights.
"He worked us in four sessions per day. We had a football pitch, a gym and an altitude trainer, we did beach runs too. The most important thing for me was to come back fitter preseason."
Shaw endured an injury-hit first season at Old Trafford, when he made just 15 Premier League starts, and was then withdrawn from contention for England's European Under-21 Championship squad.
But he believes United will be the beneficiaries in what he hopes will be an injury-free campaign.
"I had my time off, I had a few weeks to rest and recover so when we went to Dubai that was to bring our fitness levels back up," he added. "Me and Adnan really enjoyed it. Hopefully it was good for both of us.
"I just hope I don't get any injuries. I think last season was frustrating because I was picking up little niggles every time I had a couple of games."