The defender told manutd.com: "He has done well. He wants to learn and be the best in whatever he does, even in table tennis against me! You need that. All the top players have a winning mentality. They want to do well all the time, even in training.
"Last season and the season before he was faultless. He had an end product and was doing things other people cannot do. We have won back-to-back Premier League titles and the European Cup. He played a big part in that."