Carlos Carvalhal believes South Korea could win the World Cup – if they had nine other players at the level of Ki Sung-Yueng and Heung-Min Son.

Swansea City midfelder Ki and Tottenham’s Son go head-to-head at the Liberty Stadium on Saturday lunchtime in the quarter-finals of the FA Cup.

The pair are arguably the in-form players in either side, with Ki scoring in the Swans’ recent 4-1 thrashing of West Ham and Son having scored seven times in his last four games to eclipse the currently injured Harry Kane.

Swansea manager Carvalhal said: “They are both very good. If they had nine more players like that, Korea can win the World Cup.

“They are big influences in both teams – very important.”

The Swans lost 2-0 at home to Spurs in January and are just four points above the relegation zone, while Tottenham are third in the table and reached the last 16 of the Champions League.

Carvalhal added: “They lose very few games and are very hard to play against. It is David against Goliath.

“I think we are in a better moment than when we played them in the league. In this moment I think we could say we have a 30 per cent chance compared to maybe 10 per cent as we are progressing.

“They will be favourites, they are out of the Champions League so this is the trophy they can win and they will be favourites.

“But we are on the pitch to try to win and do our best to explore the weak points they have and to cover the many strong points they have.

“We will be ready for this and we are complete underdogs because this is not our main competition.

“We have an opportunity and we will give the maximum to go to the semi-finals. I trust my players and believe we can do it.”

Tottenham will be without Kane, who will not return to training until next month after damaging ankle ligaments.

Mauricio Pochettino says they will not use Kane’s absence as an excuse if they fail to reach the semi-finals and Carvalhal believes Spurs will still be formidable opposition.

“In the last game he was playing [against Bournemouth] they were losing 1-0 and he came out and they won 4-1.

“He is fantastic and I like him a lot, but at big teams, players can replace big players. All their players are international players, they are big players.”

Despite remaining preoccupied with steering Swansea further clear of the relegation zone, Carvalhal is promising they will do all they can to reach the last four.

“I have never put out a weakened team, we protect players with small injuries and problems and we will do the same here. We will not take risks, we will not change anything but we do not field a weak team

“We will try and fight and do our best. If we win, fantastic. If not, it’s not the end of the world.

“It is a big challenge, we have not reached this stage in my lifetime so it is a challenge.”