"Of course I feel very sorry because I miss already in September," said Son, referring to his involvement for South Korea at the Asian Games earlier this season.

"I feel sorry for my team-mates, the fans and the coaching staff. It's difficult.

"Sometimes you think it's a bit sad, but it is also important for my country.

"I hope I can keep my form for the national team and when I come back here again as well."

Should tournament favourites South Korea reach the Asian Cup final in Abu Dhabi on February 1, Son could potentially miss five league and cup games for Spurs.

This would include league games against Fulham, Watford and Newcastle, as well as the second leg of their Carabao Cup semi-final tie with Chelsea.

Tottenham's concern will be that Son was sluggish after he played at the Asian Games, a tournament which South Korea won.

It was only after Son had a break from international duty in November that he found the form which has seen him become one of the hottest properties in the Premier League.

"I was tired after the Asian Games because in that tournament it was playing after (every) two or three days," Son said.

"It is very important to be right mentally at the Asian Cup and to come back with a strong mind and be strong physically.

"It (November) was a turning point for me because I was tired and I didn't travel.

"It was good to have this time, some days off, and hard sessions with the team. But the Asian Cup is big for us because we have not won it for 59 years."

"I'm going there not just to enjoy it, I am going there to win something and come back with confidence."

Tottenham's win completed the double over Cardiff after their 1-0 victory at Wembley in October.

Cardiff are battling against relegation and boss Neil Warnock feels Spurs should be forced to play at Wembley for the rest of the season not to give their rivals an advantage.

Spurs were due to move into their new White Hart Lane stadium in September, but the project has suffered construction delays.

"The league should enforce they play at Wembley for the rest of the season," Warnock said. "There shouldn't be any chance of an advantage for our opponents.

"It's not our fault – we should have been playing at the new stadium ourselves.

"I think they should step in now and rather than seven or six weeks, they should make it until the end of the season now and enforce it now."

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