WATFORD'S eight-match unbeaten run came crashing to an end at Vicarage Road this afternoon after the ten-man Hornets let a two-goal lead slip against Championship leaders Sheffieid United in a pulsating 3-2 defeat.

A Darius Henderson double had put Watford on easy street but Phil Jagielka and Paul Ifill levelled for the Blades. Malkay Mackay was then shown a straight red for an off-the-ball incident with Rob Kozluk and United pushed forward, grabbing a late winner when Hornets captain Clarke Carlisle put through his own net.

Adrian Boothroyd again showed he is not afraid to alter a winning team by making two changes to the side that beat Norwich in mid-week. Lloyd Doyley replaced James Chambers at right-back and on-loan signing Carl Fletcher came in for Dominic Blizzard, while the fit again Henderson was on the bench.

Neil Warnock made just the one change to the team that triumphed at Brighton, with Ifill replacing Gillespie, who dropped to a bench that also featured Danny Webber.

The home side were first to threaten on three minutes; Matt Spring broke up a Blades attack and released King on the right. The on-loan Forest striker held the play up and played back into the feet of Spring who passed to Ashley Young in the area but, from an acute angle, he skewed the ball over the top.

Fletcher then tried his luck from 25 yards but his powerful strike was well held by Paddy Kenny.

But Watford were dealt a blow on 13 minutes when King who had started the match well was forced off with what looked like a hamstring injury, replaced by Henderson, who had been missing since the 0-0 draw with Reading with a thigh injury.

Ben Foster was called into action for the first time on the 20-minute mark, gathering Nick Montgomery's low effort after the Blades midfielder had cut into the box from the right while, at the other end, Spring headed over from 15 yards after Henderson had nodded into his path from Foster's long clearance.

Henderson then missed the first clear-cut chance of the half seven minutes before the break. Doyley burst forward down the right and played in Young who made for the by-line and crossed low but the former Gillingham striker sliced wide.

But Henderson made amends two minutes later with the opener. After Jagielka had turned Jordan Stewart's cross away for a corner, McNamee swung the ball in from the right and it was missed by Carlisle and Kenny, allowing Henderson to head home unmarked at the back post three yards out.

The visitors responded well and Alan Quinn should have done better when he was picked out by Paul Ifill in the Watford box but his first touch was heavy and, from a narrow angle, blasted over the bar.

Half-time: Watford 1 Sheffield United 0 Watford were quickly out of their blocks after the break and, after Young played a short one-two with McNamee from a corner on the left, he drove into the box and curled in a shot which Kenny did well to hold, despite having his view blocked by Devlin.

And it was no surprise when Watford doubled their advantage in the 52nd minute. Foster's long free-kick from the edge of his own box dropped on the edge of the Sheffield penalty area and Henderson took advantage of some indecision between centre-halves Morgan and Leigh Bromby to control the ball, slip inside the two and slot low past Kenny from ten yards.

But the Blades handed themselves a lifeline three minutes later. Kozluk crossed from the right and Jakielka powered a header past Foster high to the keeper's left from 12 yards.

Boothroyd responded by replacing McNamee with the more defensively orientated James Chambers but the visitors continued to press and brought on former Hornet Webber to sharpen their attack.

And United levelled 20 minutes into the second-half. There seemed no danger when Ifill picked the ball up midway in the Watford half but when he turned and headed towards the Watford box there was no challenge and his low 20-yard left-footed shot may have taken a slight deflection, as Foster struggled to read the flight of the ball.

And the Hornets were dealt another blow a minute later when Mackay was shown a straight red. With the Hornets awarded a free-kick on the edge of the Blades' penalty area, there was an off-ball incident between Mackay and Kozluk and the former Scottish international was sent off for kicking the United full-back.

Henderson was then booked as tempers threatened to boil over.

With the extra man, United piled forward and moved ahead ten minutes from time. Webber found space on the right and drove the ball across goal. Twice a United player had an effort on goal as the ball pinballed around the box and it eventually came to Keith Gillespie's who's mis-hit shot was turned into his own net by Carlisle as he tried to clear.

Foster then produced a superb stop to prevent Spring also putting into his own net after a fine Gillespie cross.

In a final twist of the tale, Stewart thought he had levelled three minutes from time when Doyley's long throw was half-cleared and he sent in an effort from the edge of the box but Kenny superbly tipped over.

Watford: Foster; Doyley, Carlisle, Mackay, Stewart; Devlin, Spring, Fletcher, McNamee; King, Young. Substitutes: Henderson for King after 16 mins; Chambers for McNamee after 58 mins; Blizzard for Devlin after 73 mins. Chamberlain, Bangura not used.

Sheffield United: Kenny; Kozluk, Bromby, Morgan, Unsworth; Ifil , Montgomery, Jagielka; Quinn; Shipperley, Kabba. Substitutes: Webber for Shipperley after 55 mins; Gillespie for Quinn after 77 mins; Nalis for Kabba after 90 mins; Tonge, Geary not used.

Bookings: Mackay sent off for violent conduct after 66 mins; Kozluk booked for a clash with Mackay after 66 mins; Henderson booked for persistant fouling after 71 mins; Carlisle for a foul on Kozluk after 90 mins; Kenny for dissent after 90 mins; Attendance: 15,399 (2,384 away support).

Referee: Mark Clattenburg (Newcastle, Tyne & Wear)