Flu-victim Gotoku Sakai has apologised to his Hamburg team-mate Dennis Diekmeier for not dropping out of the starting line-up before their Bundesliga defeat at Bayer Leverkusen.

Sakai was selected at right-back for Sunday's 1-0 defeat at Leverkusen, but had to be replaced by Diekmeier for the second half after suffering from flu.

The Japanese says he felt lethargic and should have dropped out of the matchday squad before kick-off to allow his rival Diekmeier, who became a father for the third time last week, to play the full 90 minutes.

"To be honest, I have a really bad conscience about Dennis," Sakai told magazine Kicker.

"He was fit and could play, while I had to be replaced because I still felt sluggish.

"It was disrespectful of me and I later apologised to him."

Sakai was not the only Hamburg player guilty of a poor performance in Leverkusen as Sweden midfielder Albin Ekdal's own goal gave the three points to Bayer, who had Croatia defender Tin Jedvaj sent off late in the game for a second yellow card.

Having made 25 appearances for Japan, Sakai earned his place in Hamburg's starting line-up with a strong performance in their 2-0 win at home to third-placed Hertha Berlin the weekend before.

But the 25-year-old was laid out with flu last Wednesday and Thursday and only confessed to Hamburg coach Bruno Labbadia during the half-time break that he was not fully fit.

"After that he took me off and rightly so," added Sakai.

Labbadia felt compelled to comment on Sakai's apology.

"Oh, this Japanese politeness - how nice," said Hamburg's head coach.