Watford overcame injury to three key players and the floodlights at Glanford Park cutting out on three occasions to extend their winning run to five matches at Scunthorpe United.

The Hornets struggled to recreate the form of recent weeks in a disappointing first half but the contest really came to life after the floodlights cut out eight minutes into the second half.

Scunthorpe missed a penalty after the second restart but took the lead on the hour mark through Martyn Woolford.

Danny Graham equalised four minutes later and despite the striker joining Don Cowie and Andrew Taylor on the sidelines through injury, Watford snatched victory with five minutes remaining through first-year professional Matthew Whichelow.

Watford were without their influential skipper John Eustace who had a calf injury. So Ross Jenkins made his first league start since April, with Troy Deeney and Piero Mingoia on the bench.

Scunny made two changes as Josh Wright and Garry Thompson replaced Sam Togwell and Michael Collins.

It was a very scrappy start to the contest and the first moment of note was not until the tenth minute, when Woolford's low delivery flashed a cross the box.

There was another scare for Watford a minute later when Scott Loach just gathered Thompson's knock-down before Jonathan Forte arrived six yards out.

Scunthorpe were on top at this point and Lloyd Doyley had to clear up as Michael O'Connor arrived at the far post after Loach had failed to deal with a routine back pass.

Watford regained composure and after neat play wide left, Joe Muprhy beat Martin Taylor in the air to a Cowie cross.

The visitors had to wait until the 18th minute for their first effort at goal but Jordon Mutch's long-range shot was closer to the corner flag than the goal.

Left back Eddie Nolan dealt with the threat of Will Buckley with relative ease in the first half and eventually the Watford winger switched flanks, where he found more joy.

It was Nolan's cross two minutes later which led to Scunthorpe's best chance of the half. Thompson knocked the ball back across goal but Forte's stab went wide despite the striker only being four yards out.

Watford will feel they should have scored soon after when after a spell of possession in defence, Graham's nod down from Adrian Mariappa's long ball left Mutch through one-on-one. His first touch was a little heavy though and Murphy dived at his feet.

Scunthorpe had a couple of efforts from distance go wide and blocked but it was Watford who again went closest next as Graham's goal-bound shot was blocked two yards off the line by O'Connor.

Woolford sent another dangerous ball across the box but it was the visitors who offered more of an attacking threat as the half came to a close.

Troy Deeney replaced the injured Cowie on 40 minutes and moments later the Hornets certainly should have broken the deadlock when bursting into the box three-on-one.

Graham drew the sole defender to him on the left corner of the box and although his pass was a little behind Sordell, the young striker took too long to get the ball under control and, after Scunny defenders had recovered, dragged a poor effort wide from 12 yards.

The Hornets had two half chances in the dying minutes of the half, with Mutch stabbing tamely wide after Murphy failed to claim and then Sordell's soft header easily saved.

Half time saw Watford make their second change as Andrew Taylor, who went down with an ankle injury in the opening 45 minutes, ended his final game for the club prematurely.

This resulted in a complete reshuffle of the back four, with Doyley moving to left back, Mariappa to right back and Dale Bennett coming in at centre half.

The second half was only eight minutes in when the game had to be stopped as the flood lights went out, which resulted in a ten-minute delay.

It was a completely different game after the delay as the contest really came to life.

The first chance of the half came four minutes after the second restart as a Byrne clearance fell straight to Chris Dagnall and he flashed a shot narrowly over.

England goalkeeper Loach then made a superb save low down to his left from Josh Wright.

Scunthorpe were completely over-running the Hornets at this point and they were awarded a penalty on 58 minutes when Mutch brought down Andrew Wright. O'Connor stepped up confidently but sent his effort comfortably over the bar.

But the Hornets' relief lasted just three minutes as Dagnall picked out Woolford on the corner of the area and he found the bottom corner to make it 1-0.

However, the drama continued as Watford levelled just four minutes later. A very poor header back to Murphy was read by Graham and the striker headed past the keeper for his 16th of the season despite the best efforts of David Mirfin.

This was to be Graham's final contribution as he went off for Whichelow moments later after struggling with a hamstring problem.

The chaotic second half continued though as the lights went off for a second time with 19 minutes remaining. The game was restarted after another delay only for the lights to go out for a third time.

The lights did come back on and Watford created a chance almost immediately as Sordell was ready to pounce on Deeney's cross when Byrne headed calmly back to Murphy.

Watford were on top and sent in a number of crosses in quick succession with Scunthorpe camped in their own box.

But an aimless clearance from Andrew Wright almost saw Scunny through to score as Bennett received a lucky deflection, when on the floor, just as Woolford was set to shoot.

Whichelow played well after his introduction and his low cross was just too far ahead of Buckley who was arriving in the box.

The contest lost its edge for a while but came back to life a little as the game entered the final ten minutes.

Watford continued to throw bodies forward in search of a winner and not long after Buckley had sliced an effort wide, Sordell tamely side footed an effort into the arms of Murphy.

But the Hornets willingness to throw bodies forward paid off with five minutes remaining as Whichelow latched on to a flick-on and lifted the ball over the on-rushing Murphy to secure a well-fought victory.

It is now five consecutive victories and seven matches unbeaten for Watford, who remain in the play-off places.

Scunthorpe: Murphy; Wright, Mirfin, Byrne, Nolan; Thompson (Cowan-Hall 73), O'Connor (Togwell 72), Wright, Woolford; Forte (Godden 65), Dagnall.

Subs: Slocombe, Raynes, Collins, McClenahan.

Watford: Loach; Doyley, Mariappa, M Taylor, A Taylor (Bennett 45); Jenkins, Mutch; Cowie (Deeeny 40), Sordell, Buckley; Graham (Whichelow 66).

Subs: Gilmartin, Thompson, Walker, Mingoia.

Attendance: 4,498 (614).

Referee: Andy Haines.