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Dover drew their second consecutive blank of the week after being held to a goalless draw by Guiseley in the Vanarama National League clash at Crabble on Saturday.
Boss Chris Kinnear's side, who drew 0-0 against Braintree at the venue on Tuesday, dominated the game against the promoted Yorkshire visitors but couldn't make the pressure count.
But defender Sean Raggett should have won it for Dover in the 88th minute but saw his free header from Nicky Deverdics' free-kick crash into the bar.
That summed up another frustrating day for the home side.
Guiseley offered very little in attack with Mitch Walker making just two saves in the game.
Dover started brightly with Liam Bellamy's surging run into the box ending with the midfielder firing just over the bar in the fourth minute.
Duane Ofori-Acheampong went even closer in the 17th minute after a shot on the turn thundered into the side netting.
Visiting goalkeeper Steve Drench denied Stefan Payne minutes later, showing a strong hand to turn away Payne's shot in a one-on-one.
Dover were asking all the questions and Drench produced a stunning save from Ofori-Acheampong's shot.
Payne saw his effort blocked following Ricky Miller's quality pass before Sam Magri's shot from inside the box was charged down.
Miller had the ball in the net in the 44th minute but his celebration was short-lived - the referee had already blown for a Dover free-kick.
And from it, Drench produced a sensational double save to keep Dover out.
Payne took the kick and Drench pushed it away before he somehow saved Miller's close-range effort from the rebound.
Payne had the first couple of chances in the second half, seeing his diving header cleared for a corner before hooking Sean Raggett's knockdown from the resulting kick wide eight minutes in.
Kinnear made a change in the 63rd minute replacing Miller with debutant Toby Ajala.
And it didn't take long for him to make an impression with the winger crashing a shot into the underside of the bar in the 70th.
Whites were getting closer but a goal never came although Raggett should have ensured one did.
Dover: Walker, Raggett, Grimes, Orlu, Magri, Miller, Bellamy, Thomas, Miller (Ajala 63mins) , Ofori-Acheampong, Payne. Subs not used: Wynter, Sterling, Diallo, Rafferty. Attendance: 823