Chris Wilder’s first home game as Watford’s new manager ended in a straightforward 3-0 victory over Birmingham.
Imran Louza and Keinan Davis scored within the first 16 minutes of a painful evening for Blues manager John Eustace – a former Hornets captain as a player.
Birmingham improved in the second half but could not prevent substitute Britt Assombalonga from adding a third.
Wilder’s first game as Slaven Bilic’s successor had been a disappointing defeat at QPR on Saturday, but this result revived hopes of making the play-offs and left Birmingham still too near the relegation places for their liking.
The home fans gave Wilder, Watford’s third manager of the season, some polite applause moments before kick-off but had a goal to cheer within six minutes.
Davis picked out Ken Sema in space on the left and Louza got in front of Harlee Dean to thump the ball home from seven yards.
Birmingham were caught on the break in the 16th minute and allowed Aston Villa loanee Davis to double the lead.
Louza supplied the pass for Davis to power into the box on the left and, having got the better of defender Kevin Long, smashed a rising drive past goalkeeper John Ruddy.
Defender Jeremy Ngakia almost made it 3-0 with an long-range strike that pinged off a post.
Birmingham looked shellshocked and were relieved once again when Ismael Kone fired narrowly wide after Sema’s clever backheel had sent Joao Pedro into space.
Craig Cathcart headed inches past the back post as Blues continued to live dangerously, while offering nothing at the other end.
It was a different story after the break, though, and Scott Hogan, one of two half-time substitutes for the visitors, poked a great chance wide within two minutes of the restart.
Krystian Bielik had put Hogan through – and the defender forced Hornets goalkeeper Daniel Bachmann into a near-post save shortly afterwards.
Davis was booked for a late tackle on Auston Trusty, who then volleyed a great chance to reduce the arrears over the crossbar from Jordan Graham’s delivery to the back post.
Graham’s fine pass set up Hogan again and this time the Austrian could only parry. Lukas Jutkiewicz seized on the loose ball but only after nudging over Wesley Hoedt – and his shot hit the Watford man anyway.
Blues’ hopes of a comeback were extinguished in the 73rd minute when substitute Assombalonga bundled the ball past Ruddy from close range from Kone’s cross from the right.
It was the January signing’s first goal for the Hornets in his second spell, having begun his career at Vicarage Road as a teenager.
Bachmann pulled off a stoppage-time save to deny substitute Jordan James a long-range consolation.