An entertaining clash at Vicarage Road ended all square, between the Blades and the Hornets.
Both teams had chances to win all three points, with Dean Henderson twice coming to the Blades rescue in the second-half.
For the clash in Hertfordshire, boss Wilder named the same starting XI that pushed leaders Liverpool close last time out. Amongst the substitutes, Sharp returned following a three-match ban and replaced Clarke.
It was a quiet opening few minutes, with both sides looking to get a grip of the game, although it was the Blades pushing forward the most often, with Baldock forcing a corner, that Egan almost made something of at the back. But in the 10th minute, United had a huge let off, as Gray somehow put the ball over the ball with an empty net in front of him, after Pereyra had made the most of some indecision down the Blades left.
That chance lifted the home crowd and Pereyra forced a corner, after Welbeck had ran purposefully through midfield, but Prödl headed harmlessly over at the back post. Back on the attack, Norwood's switch of play found Baldock in acres of space and his deep cross forced Janmaat to take action and concede a cornrer. That was partially cleared, before Basham's deflected cross nearly resulted in Cathcart turning the ball into his own net. A flurry of attacks ended with Fleck forcing Foster into a save.
The Blades were now on top, although Watford posed a threat on the break and Baldock forced another couple of corners in quick succession, but despite good delivery they unfortunately came to nothing. United continued to press for the opener, but McBurnie couldn't connect at the near post after another marauding run forward from Basham.
As half-time approached it was again the Blades going forward, but from Basham's header down from Stevens cross, Robinson couldn't make a clean connection and it remained goalless at the break.
On 49 minutes, United had Henderson to thank for keeping the scores level. Gray flicked on before Welbeck got the better of Egan and advanced clean through from the halfway line, but the Blades stood big and denied the former Arsenal man at the expense of a corner. At the other end, Lundstram got the better of Prödl, McBurnie headed down and Robinson's strike almost got the better of Foster.
McBurnie was the first player to be booked following a foul and a disagreement with Kabasele. Just after the hour, McBurnie was replaced by Mousset, who received a warm hand from the visiting supporters. Wilder made his second change with 19 minutes, as Sharp took the place of Robinson.
With the clocking ticking down, Fleck had a shot blocked, which resulted in a break for the home side, but Deulofeu's cross was comfortably collected by Henderson. Watford surrendered possession in their own half, before Sharp's cross almost caught Foster out, only for the ball to land wide of the back post.
Five minutes of added time were signaled and Lundstram was booked, having clipped the heels of Deulofeu to halt a potential break and it was Henderson who preserved the point at the death, denying Dawson, from Deulofeu, as the game ended all square.
Watford: Foster, Janmaat, Prödl (Dawson 57), Cleverley, Welbeck (Sarr 77), Cathcart, Doucouré, Gray (Deulofeu 59), Holebas, Kabasele, Pereyra.
Unused: Gomes, Chalobah, Hughes, Femenía.
Blades: Henderson, Baldock, Stevens, Fleck, O'Connell, Basham, Lundstram, McBurnie (Mousset 62), Robinson (Sharp 71), Egan, Norwood.
Unused: L. Freeman, Jagielka, Osborn, Moore, Bešić.
As it happened...
Blades to kick-off,
We are underway!
Blades on the attack as Robinson runs the channels.
United force an attacking throw and from the eventual cross the home side clear. 0-0.
United have started the better and Stevens rasises some alarm bells with a terrific cross from the left.
Some stout defending early doors from the hosts who clear. 0-0.
Janmaat's cross for Watford is plucked out of the air by Henderson who shows confidence coming a long way for a successful claim. 0-0.
Baldock raiding down the right wins a corner for the Blades.
Fleck delivers to the far post and Egan heads into a dangerous area but Watford clear. 0-0.
What a chance for hosts.
An attack down the right sees a cross into the six yard area, Henderson fails to get something on it at full stretch but Andre Gray puts it over from six yards with the goal empty.
Replays suggest Gray may have been offside. 0-0.
Prödl puts a header harmlessly over from a corner as the home side enjoy a good spell. 0-0.
Some more good defending from the hosts as Baldock delivers a dangerous cross towards the back post where Robinson was lurking.
Watford turn it behind for a corner which is cleared.
Awkward moment for Cathcart who turns a cross towards his own goal but it is clawed away by Foster. 0-0.
Trademark driving run forward by Fleck towards the edge of the area but the shot is comfortably held by Foster. 0-0.
United lucky not to be caught on the break there as Watford were streaking forward with a 3 on 1 advantage, but the killer pass goes straight to Stevens who clears. 0-0.
Great spell by United who bombard the Watford area with crosses.
Baldock looked to be in at the by-line but again Watford clear in the nick of time.
Baldock pinches the ball back for United as Watford try and shepherd the ball out for a goal kick.
The wing back drives into the area but just as he is about to cut it back, Holebas recovers to nip back and retrieve the ball. 0-0.
Pereyra threatens down the right for Watford but O'Connell stands his ground and makes the challenge.
The ball goes out for a corner which United clear. 0-0.
Half-a-chance for United after some patient build-up play down the right.
A low cross into the near post from Basham just eludes McBurnie at full stretch, and Foster gathers. 0-0.
Doucouré takes aim from distance but Norwood with a brilliant block at full stretch. 0-0.
O'Connell tussling with Gray, the defender almost makes a mistake to let the striker in, but recovers in time to clear. 0-0.
Stevens with a deep cross which is attacked by Basham, the loose ball comes to Robinson but he can't make a clean connection and Foster gathers.
Watford 0 - 0 Blades
Second half underway...
Best chance of the game so far.
Welbeck beats Egan to the ball on halfway and sprints clear on goal, but Henderson makes a brilliant save with his feet to keep it level. 0-0.
Chance for United!
Lundstram does really well to hook a cross into the area. McBurnie rises and the loose ball falls kindly for Robinson who hits it first time but Foster makes the save. 0-0.
Stevens takes aim from distance but smashes straight over. 0-0.
Change for Watford as Prödl comes off injured and is replaced by Craig Dawson.
Booking for McBurnie for a late challenge
Game is stopped so O'Connell can get treatment, he's okay to continue though...
Second change for Watford as Deulofeu replaces Gray.
Blades make a change as Mousset replaces McBurnie.
Well, United looked to counter with a ball over the top for Robinson but the referee has blown as Watford have a man down. 0-0.
Change for United as Billy Sharp comes on for Robinson.
Fleck's cross takes a deflection and goes behind for a corner.
Norwood's inswinger is claimed by Foster. 0-0.
Sub for Watford as Welbeck comes off and Sarr is on.
Fleck shot is blocked and the rebound sets Watford off on a counter which eventually comes to nothing as Henderson claims a cross from the byline.
Norwood delivers a free-kick which is headed clear. Lundstram is there just inside the area but skews his effort over. 0-0.
Sharp drills a low cross into a dangerous area, but again Watford clear. 0-0.
Sharp works out wide and looks to cross. It is deep and initially looks too close to the 'keeper but it almost dips in as it sails just beyond the far post.
Watford counter is halted by Lundstram who is booked.
Five added minutes
Chance again for Watford as Deulofeu's free-kick is headed towards goal by Dawson and Henderson makes a wonderful save to keep it at 0-0.
Watford 0 - 0 Blades