The Swansea coach says his squad will be up against very tough opponents when the two sides meet this weekend. Swansea were defeated 2-0 on home-ground when they last clashed with 'Spurs' in January.
Tottenham are currently occupying third position in the Premier League, in contrast with Swansea, who are just four points clear of the relegation zone.
In an interview with 'SkySports', Carvalhal said of 'Spurs' that ''they lose very few games and are very hard to play against. It is David against Goliath.'' Although he noted that Swansea 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.''
The Portuguese acknowledged that Tottenham will be the obvious favourites but added that he had faith in his players. He said their challenge would be ''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."
Swansea will not have to contend with Harry Kane, who will not be returning to training until next month following an ankle injury. However, Carvalhal does not however underestimate his opponents without their star striker, he said ''he [Kane] 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."
The 'Swans' boss reiterated that his squad would ''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.''