Watford did what was required on a night when the leading protagonists in the Championship again underlined how competitive the race for automatic promotion is by beating Rotherham United 3-0.

The Hornets were again short of their best in the first half but they were gifted the lead when a Kari Arnason lapse let in Odion Ighalo for his 16th of the campaign.

But the game was effectively won before the hour-mark was up by two goals in as many minutes, as Troy Deeney scored after Adam Collin had been unable to hold onto a Daniel Tozser free-kick and then a mistake from the Rotherham keeper allowed Ighalo to make it 14 goals in his last ten league appearances.

Slavisa Jokanovic opted for two changes from the side that was beaten 3-0 by Norwich City on Saturday and also decided to alter the formation to 4-3-1-2. In came Tommie Hoban and Tozser, with Juan Carlos Paredes and Ikechi Anya dropping to the bench.

Rotherham conceded two goals more than the Hornets as they were thumped 5-0 at Wolves on Saturday and boss Steve Evans decided to make twice as many changes as his counterpart. Jack Hunt, Craig Morgan, Ben Pringle and Conor Sammon were promoted to the starting line-up, as Kirk Broadfoot, Frazer Richardson, Danny Ward and Adam Hammill dropped to a bench that also numbered former Hornets goalkeeper Scott Loach.

The Hornets had the first sniff of an opening inside 90 seconds when Almen Abdi showed fine control and then good acceleration to break down the left before passing inside to Igahlo. He in turn found Miguel Layun, but the Mexican’s attempts to keep the move going were snuffed out.

Watford continued to probe in the opening stages but the signs were it may be a night when patience would be needed, as the visitors were content to let their opponents have the ball for the most part and seek to prise them open.

However, the home side almost did that in the 11th minute when a mishit clearance fell for Igahlo, he left Morgan trailing and tried to set up Deeney in the centre of the penalty area, the ball was half-cleared away to Tozser and his well-struck follow up from 20 yards was blocked.

The Hungarian had another opportunity six minutes later, this time firing over from a similar distance, after good work from Deeney and Layun as the absence of any natural width to the home side’s play continued to be all too apparent.

But the Hornets didn’t have long to wait to make the breakthrough as when the ball was played back to Arnason around 25 yards from his own goal, he slipped under no real pressure and Ighalo pounced, rounding the stranded Collin to roll in goal number 16 of the season.

But the athleticism of the Rotherham keeper, his side would have been 2-0 down by the 25th minute as Collin made three fine saves within a minute.

First he plunged to his left to keep out a low Abdi drive, then the keeper went the other way to keep out a curling Deeney strike. But the best save of the three was to be the last as from Tozser’s resultant corner, Joel Ekstrand tried a deft back-heeled near-post flick which Collin clawed into the air before Hunt cleared from close to his line.

Having been gift-wrapped the lead, the hosts almost tried to return the favour in the 31st minute when a mistake from Ekstrand gave Matt Derbyshire a clear run in on goal from the left side of the penalty area, but Heurelho Gomes was equal to it and saved well.

The Millers kept the pressure on though, winning three corners in quick succession as Watford struggled to assert themselves defensively, and from the third the visitors should have equalised but an unmarked Morgan directed a free header straight at Gomes.

Watford had been unable to create too much in the final third during this spell but they did have a chance two minutes before the break when Deeney’s strength enabled him to lay the ball off to Ighalo on the edge of the area. As benefiting a player in confident mood, the Nigerian opted to take it first time but he got under his left-foot effort and put it over.

The start of the second half got off to a relatively even start but by the 56th minute the Hornets had put the game to bed.

Rotherham’s problems started in the 53rd minute when Arnason felled Tozser around 35 yards out and he picked up the game’s first yellow card for his troubles.

Tozer lined up one of his long-range blasts and fired a left-footed strike straight down the centre of the goal, Collin got behind it but was unable to hold on, Ekstrand reacted first to the rebound and centred for Deeney to tap in and make it 2-0.

Within just over a minute, the Hornets had a third. Collin failed to hold on to a Layun shot and the ball squirmed from his grasp for Ighalo to apply another straightforward finish and double his tally for the night.

Watford had their tails up and Hoban was the next to try his luck, jinking his way past an opponent on the left side of the area before rifling in a shot that flew over.

The visitors made their first change in the 65th minute when Ward replaced Robert Milsom. Abdi then warmed Collin’s gloves with another strike before Layun made way for Gianni Munari.

Rotherham asked a few questions of the Watford defence as they tried to look for an unlikely route back into the game before both sides made another change. Another good night’s work by Ighalo was ended when he made way for Matej Vydra, while Hammill replaced Conor Sammon.

Tozser wasn’t too far wide of the near post with a curling 25-yard free-kick after Richard Smallwood had been booked for a foul on Abdi and then the Swiss midfielder sent a dipping effort at Collin.

The chances kept coming as a Tozser corner from the right was played short to Vydra and his cross to the far post was put behind for another set piece for the Hornets.

And an even better opening came and went when the hosts countered and Deeney sent a teasing low delivery across the penalty area and a stretching Abdi was unable to keep his effort below the bar.

That was to be the Hornets’ skipper’s last involvement as he was replaced by Fernando Forestieri, before Derbyshire saw two efforts in quick succession deflected behind at the other end.

Jonson Clarke-Harris was given a run out for the closing stages in place of Derbyshire as the Hornets endured a few nervous moments in the closing stages, as did their opponents.

Vydra forced a good save out of Collin with a well-struck effort before Abdi looked certain to add a fourth in injury-time when he beat the Millers keeper with the outside of his right foot, only to see the ball rebound away off the upright.

Watford: Gomes; Cathcart, Ekstrand, Angella, Hoban; Layun (Munari 68), Watson, Tozser; Abdi; Deeney (Forestieri 84), Ighalo (Vydra 64). Not used: Bond, Munari, Paredes, Pudil, Anya.

Rotherham United: Collin; Hunt, Morgan, Arnason, Fryers; Green, Smallwood, Milsom (Ward 65), Pringle; Sammon (Hammill 74), Derbyshire (Clarke-Harris 87). Not used: Loach, Broadfoot, Bowery, Richardson.

Bookings: Arnason for a foul on Tozser (53); Smallwood for a foul on Abdi (76).

Attendance: 13,468 (301 away).

Referee: Andy Davies.