Watford's charge towards automatic promotion continued with a convincing 3-0 win over Birmingham at Vicarage Road.
Goals from Ken Sema, Nathaniel Chalobah and Andre Gray saw them tighten their grip on second spot.
It was a thoroughly-deserved victory for Xisco Munoz's side, who made it five successive victories in the Championship.
Any confidence Birmingham had gained from their midweek victory over Reading in new manager Lee Bowyer's first game in charge, was dented after just four minutes.
Joao Pedro's powerful shot from the edge of the area was parried by Neil Etheridge straight into the path of Sema, who gleefully tapped home.
Watford should have eased further ahead from an 18th-minute corner. Sema's in-swinger was allowed to drop to the ground at the far post where Watford left-back Adam Masina somehow contrived to send his half-volley into the advertising boards instead of the back of the net.
The home side were indebted to midfielder Chalobah for preserving their lead after 24 minutes.
Birmingham had begun to press forward and when Alen Halilovic swung over a cross that eventually dropped in front of Jeremie Bela, Chalobah threw his body into the path of the Angola international's shot.
The clearer chances kept coming at the other end. Chalobah's midfield partner Dan Gosling played a long one-two with Pedro before heading the return cross just over the bar.
Another intricate Watford move eight minutes before the interval would have been finished by Isaac Success had Harlee Dean not stretched to touch the ball away from the striker.
Moments after Success had dallied when through on goal early in the second half and allowed Etheridge to smother his shot, the home side extended their lead.
Gosling swung a 55th-minute corner which was headed home at the far post by the unmarked Chalobah.
The destination of the points and the diverging paths of the two sides appeared set even then. Watford made a double substitution immediately after the second goal, indicating Munoz's confidence that the victory was secure.
Bowyer, by comparison, made a triple substitution in his desperation to rescue at least a point from the contest.
The most telling message came from high above Vicarage Road 10 minutes later when a plane hired by a group of disillusioned Birmingham supporters trailed a banner which read: 'By order of Blues fans Dong must go' - a pointed message to chief executive Xuandong Ren.
It had no effect on events on the pitch. Moments after Munoz had made another double substitution, the players he brought on combined to make it 3-0.
Jeremy Ngakia dispossessed Kristian Pedersen and fed Gray, who raced forward and slipped his shot beyond Etheridge.
What the managers said...
Watford's Xisco Munoz: "I am very happy with everyone after five wins in a row, the first time for us in the Championship, but give me one day free, please. The Championship is very hard. We have a little more time for work now. I don't know if it's good or not, but I know that the players need their rest.
"I am lucky, believe me, that I have 24 players and it doesn't matter who plays when you see players give 100 per cent focus in our challenge for promotion. Our fans enjoy the fact that our players give everything. Everyone gives their best in attack and in defence. Because of that, we have one clean sheet more."
Birmingham's Lee Bowyer: "Watford have come down from the Premier League and you can tell the difference. For me they are going straight back up. You could tell the difference in every aspect of their game, particularly the physicality of their defending and the way they defended their box.
"They kept getting through our press for the first 10, 15 minutes, but we changed it and at times we looked more likely the team to score next. It was just the quality. Watford were more clinical, weren't they. But we moved the ball really well today and Watford couldn't get near us at times. If you are going to put in performances like that against top, top sides then it should give us an edge against the teams around us."