With the winners set to welcome Manchester United in a televised fourth-round fixture on Sunday, there is plenty of incentive for Rovers to pull off another upset.

"We know this game will be tough," Pedro said in an interview on the Watford YouTube channel.

"I think they will have hope. Like in the last game, when we went 3-0 up in the first half and in the second half they managed to get a draw, so I think for them at home, they will try to win and qualify (for the next round).

"We have to go there, win the match and come back to Watford having qualified."

Hornets manager Nigel Pearson is again expected to make changes as his side battle for Premier League survival and face a third game in the space of six days following on from Tuesday's last-gasp defeat at Aston Villa.

Pedro was one of several players drafted in for the original third-round tie and the 18-year-old former Fluminense forward looks set to be involved again.

"I was very happy with my debut and felt really comfortable too," said Pedro, who signed a five-year deal which was officially lodged on January 1, 2020, after having to wait for a work permit application.

"My team-mates gave me confidence and made me feel at ease.

"Obviously there is always nerves, but after my first bit of play at the beginning of the game, I felt more settled."

Swapping the warmer climes of Rio for chilly Hertfordshire, though, has proved a testing transition.

"In Brazil, the game is a bit slower. Here the game is faster and the space is tighter," Pedro said.

"But the only thing I think I need to get used to is getting used to breathing the cold air, which is something different for me and is really tough."

Midfielder Nathaniel Chalobah is a doubt after a hip problem forced him off during the closing stages on Tuesday night at Villa Park, where a stoppage-time 2-1 defeat saw Watford drop back into the relegation zone.

Forward Ismaila Sarr is another player unlikely to feature as he recovers from a hamstring issue.