South Korea coach Paulo Bento has dismissed concerns over captain Son Heung-min's fitness, calling on his supporting cast to step up in Friday's Asian Cup quarter-final against Qatar.

The Koreans, who have mysteriously gone 59 years without winning Asian football's most coveted prize, have already lost Newcastle midfielder Ki Sung-yueng to a hamstring injury while Son looked badly fatigued in their extra-time win over Bahrain earlier this week.

With Tottenham manager Mauricio Pochettino sweating over Son's fitness, having lost Harry Kane and Dele Alli to injury, Bento on Thursday sought to take some of the pressure off his talismanic skipper before facing the Qataris in Abu Dhabi.

"Obviously we can't do anything about Ki now," shrugged the former Portugal boss.

"But we have to find the best solutions, not find the best excuses. It's not the first time the players will play twice in three days and it won't be the last.

"It's not mandatory that Son scores goals," added Bento, asked about his misfiring forward, who arrived after South Korea's first two games and played in the last two.

"It's not important for me who scores -- the most important things is that the team scores and is creating opportunities."

Son arrived in the Emirates after appearing in a punishing 13 matches for Spurs since the beginning of December and immediately played 87 minutes in South Korea's 2-0 group-stage win over China.

But Bento has few qualms about pushing his mercurial playmaker to the absolute limit as South Korea look to end a 59-year title drought -- whatever the fears of nervous European club managers.

"I prefer the best players to play every game," he said.

"Of course that can be a concern for my (club) colleagues, but not for me. In the last few months when the national team met up, we've been without players too."

Meanwhile, Qatar coach Felix Sanchez tipped his players to push South Korea all the way as the tiny, oil-rich state looks to reach the semi-finals for the first time.

"South Korea are one of the favourites in the tournament for a reason -- they are a very attacking team and they play proper football," said the Spaniard, whose side beat former champions Iraq 1-0 in the last 16.

"But we came to show we can compete with the most powerful teams in the continent and so far we have managed that. My players are confident and they will be ready."

Qatar, 3-2 winners the last time they met South Korea, in a World Cup qualifier 18 months ago, have face constant abuse from Asian Cup crowds over the long-running Gulf blockade of the country.

But Sanchez, whose Sudan-born forward Almoez Ali has scored seven goals in four games and poses arguably the greatest threat to the title-chasing Koreans, praised his side's commitment.

"The players are managing the situation very well," he said. "They're showing great team spirit. They feel the pressure -- but they feel it in the right way."