Watford’s problems are mounting again after they suffered a third straight league defeat with a 3-0 loss at Birmingham City.

Two of the goals came from an unexpected source, centre-half Curtis Davies, who capitalised on poor marking to head the Blues in front nine minutes before the break before he doubled his tally with a far-post header from a corner on the hour-mark. Chris Burke then made certain of the points for Chris Hughton’s in-form side with the third eight minutes from time.

The Hornets had gone into the game with a change of approach, deploying a five-man midfield behind lone striker Marvin Sordell. The signs prior to Birmingham taking the lead - and for a spell at the start of the second half - had been encouraging but, as with last week’s defeat to Reading, Watford lacked a creative edge and end product, managing just four goal attempts in the whole game and only one of which was on target.

Sean Dyche made just the one change from the side that suffered a late defeat against the Royals seven days previously. Jonathan Hogg returned after missing that game with a knee injury, with Craig Forsyth dropping to the bench.

The result of this was Watford opened the contest with a 4-1-4-1 formation, with Hogg playing the main sitting role in front of the back four, John Eustace operating more advanced and Prince Buaben the furthest forward of the three central midfielders. Mark Yeates switched to the left, with Troy Deeney offering offensive support to Sordell from the right.

The Hornets were the better side in the opening stages on a pitch that was wearing in places, looking confident and retaining possession well and they created the first opening in the ninth minute Hogg played a fine angled pass to the right side of the area to put Marvin Sordell through towards goal but with the angle against him. The Hornets top scorer initially looked to square the ball, with keeper Boaz Myhill trying to second guess his opponent, but with Buaben crowded out, he played it back to Deeney, who tried to come inside but was up against too many blue shirts.

Watford continued to be positive but they were almost caught out on the counter-attack in the 17th minute when the pacey Burke attacked and beat Carl Dickinson on the outside before sending over a deep cross that Scott Loach had to claw away. The ball was instantaneously played back into the danger zone by Vicarage Road old boy Marlon King but he was unable to pick out a team-mate.

Although it took the visitors until the 24th minute to have their first attempt – Yeates dragging a left-footed effort from the edge of the area well wide – the start to the match had being encouraging, particularly from the five-man midfield.

Eustace was also off target with a half-volley from 18 yards soon after before Birmingham’s other player with strong opposition connections, former loanee Jordon Mutch, mustered the first on target attempt of the game, but Loach was always comfortably behind his curling effort from inside the D.

However, it took some smart defending from Lee Hodson to prevent Mutch going closer with his next effort in the 34th minute – the right-back getting marginally in front of the onrushing midfielder to deflect his header from Burke’s right-sided cross over the top. But Birmingham were not to be denied for much longer.

Following the resultant corner from the left, the ball was kept alive and Keith Fahey flighted over a cross from the right side of the area and Davies was not picked up as he planted a firm header past the helpless Loach to make it 1-0 to the hosts.

And that was the way it stayed until the interval, although the visitors could have perhaps made more of a free-kick in injury-time when Yeates’ delivery from the right was missed by a defender and the ball rather hit Buaben, who was not alert to the situation.

King’s afternoon against his former club came to a premature end in the 51st minute when he was replaced by Adam Rooney because of what looked to be a groin injury, but moments later Byhill had to get sharply down to his left to keep out a snap shot from Deeney.

Like in the first half, Watford were the brighter of the two sides in the opening minutes of the second period, only to find themselves two down on the hour to Davies’ second of the match.

The situation again arose from a corner after Burke had come in off the left flank and seen his shot blocked behind, but this time the set piece was struck deep beyond the far post where Davies arrived late, and unmarked again, to send a fine header back across goal to put the Blues firmly in control.

Nikola Zigic earned the game’s first yellow card on 63 minutes for persistent fouling before Dyche decided to make his first change, with Chris Iwelumo replacing Buaben.

Watford tried to get back into the game, without really threatening, but the next chance came Birmingham’s way with 11 minutes remaining when Zigic tamely headed a cross from the left through to Loach.

But Birmingham made the game safe with eight minutes remaining when Burke drilled a shot from the right side of the area past Loach after the Hornets keeper had pulled off a tremendous save to keep out Jonathan Spector's looping header following a ball in from the left side of the area.

Both sides made changes soon after – Wade Elliott and Nathan Redmond replacing Zigic and Jean Beausejour for the hosts and Hogg making way for Ross Jenkins – before Loach was again forced into a save to prevent Redmond from making it four with a low drive from the left side of the area.

Birmingham City: Myhill; Caldwell, Davies, Murphy; Burke, Mutch, Fahey, Beausejour (Redmond 84); King (Rooney 51), Zigic (Elliott 84). Not used: Doyle, and Gomis.

Watford: Loach; Hodson, Nosworthy, Mariappa, Dickinson; Hogg (Jenkins 84); Deeney, Eustace, Buaben (Iwelumo 71), Yeates; Sordell. Not used: Forsyth, Doyley and Bond.

Bookings: Zigic for persistent fouling (63); Dickinson for persistent fouling (88).

Attendance: 18,681.

Referee: Trevor Kettle.