Emil Riis scored his first Bristol City hat-trick as the Robins claimed an emphatic win over fellow Championship side Watford to sail into the fourth round of the FA Cup.

City opened the scoring in just the second minute as Riis guided in a powerful header from Neto Borges' looping cross, and the scorer turned provider to set up Anis Mehmeti for the hosts' second.

Robins defender Rob Atkinson nodded home a third before Riis netted twice more to put the game to bed and claim the match ball either side of Jack Grieves' consolation for Watford.

The Hornets had won four successive matches in an undefeated run of seven games but their much-changed starting XI was unable to pose any real threat upon their lively hosts.

City took the lead early after a long ball from Mehmeti reached Borges, who lofted it over to the back post for an awaiting Riis to head into the net.

Watford responded well, with Vivaldo Semedo sending a shot wayward before Nestory Irankunda thundered his direct free-kick high and wide.

However, the visitors' upturn did not last and Bristol City doubled their lead in the 37th minute as captain Jason Knight found Riis in space. The Dane then cut a ball across goal for an oncoming Mehmeti to fire into the net.

Riis twice missed chances to extend the lead after the break but Atkinson beat the keeper to head home Scott Twine's curling free-kick for the third, before Riis was again picked out by Neto Borges to slot home a fourth.

The Robins were unable to keep a clean sheet after Irankunda stormed down the left flank to seek out Grieves for Watford's consolation.

City, though, would have the last word when on-loan West Ham midfielder George Earthy, who returned to Ashton Gate on Friday after a successful loan spell last season, set up Riis to seal his hat-trick.

Bristol City boss Gerhard Struber told BBC Radio Bristol:

"With performances like that, my personal expectation grows and also the boys' expectation. What is in the bottle, what can you bring on the day, I think today we showed it many, many times.

"When we play like that, especially with Watford, a really big team with outstanding pace, with so much dynamic, it's not easy to deal with and my boys did it at a great level.

"Performance wise, we have been for the last two weeks on a really good level. I think every single player went a little bit out of their personal comfort zone.

"We can dream for the next round and also for the Championship. But also I think with performances like that, this is a statement. For us, for ourselves but also in all directions."

On Emil Riis: "He's a really good striker and [with] more performances like that, with bigger consistency, then I think it's normal that we can win like that against top teams at this level."

Watford boss Javi Gracia speaking to BBC Three Counties Radio:

"Before the game, I spoke with the players and I explained to them how important this competition is for me. The good memories I had after my experience of arriving at the FA Cup final [with Watford in 2019].

"The team wanted it but the first half we competed better than in the second. The first half we had some chances that we didn't take and the opponent scored their goals.

"After that, in the second half, we didn't compete how we have to.

"I don't really know what happened in the second half but we conceded. We were soft defending, we conceded many chances for the opponent. It something we have to speak about and try to improve if we want to keep our level in the Championship."