Striker Wilfried Bony is proving what a "beast" of a player he is after his club record signing for Swansea, according to first team coach Alan Curtis.
The Ivory Coast international scored the Swans' winner in their first win over Manchester United at Old Trafford.
Bony's 90th minute header sealed the 2-1 win in the FA Cup on Sunday.
"His strength and power are quite frightening - he is a real beast of a man," said Curtis.
Swansea will face either Birmingham City, Crawley Town or Bristol Rovers in the fourth round.
Bony has now scored three goals in two games for the Swans and produced in a man-of-match performance with a brace in the 3-2 defeat to Manchester City the previous week.
He became the club's record signing when he signed for £12m from Dutch side Vitesse Arnhem in the summer of 2013.
Bony has now scored 13 goals in 27 appearances for Swansea.
"It took him a while to settle in," said Curtis.
"He scored a lot of goals last season, but he missed out on pre-season with us so he was playing catch up.
"The fact he came for £12 million meant people expected a lot from him.
"But he was just short of fitness and throughout the season we have worked on that...
"...He already has 13 goals this season and his latest one was a cracking goal."
Curtis also pointed to the performance of Swansea's other goalscorer Wayne Routledge in the win over United.
"Wilfried will obviously take the headlines for his winning goal, but Wayne's performance was fantastic.
"He is a confident player and he has all the ability in the world. He can beat people, has terrific strength and can hold people off. He certainly delivered.
"It was a great team performance. We made quite a few changes but people certainly stepped up to the mark.