The midfielder has linked up with the tour party later than the rest of the first-team squad and is now upping the ante in a bid to prove his readiness ahead of the season opener at Swansea on August 17.
At the forefront of Kagawa's mind, though, is a reunion with former side Cerezo Osaka on Friday, which he is relishing.
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|10/11||Shinji Kagawa is 10/11 with William Hill to score at anytime v Cerezo Osaka
"My current position is I've just rejoined the team and I've been training on my own during my break because I really need to catch up with the other players.
"I think the first match of the season will be very important so I don't want to get myself injured but I can promise I will play at my best [against Cerezo Osaka]."
Big things are expected of Kagawa after a stop-start 2012-13 season, but the playmaker understands how difficult it will be to make a starting spot his own under new manager David Moyes.
He added: "Last year, I knew there would be a lot of competition within the team for me to be in the starting line-up. I knew it's a big club and it would happen.
"I really need to show results and there are so many things I have to do like work hard every day. I will be playing in my home country tomorrow and I want to focus on the game to be able to perform at my best."