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Dover are left to concentrate on winning promotion from Blue Square South after losing at holders Stevenage in the FA Trophy on Saturday.
Andy Hessenthaler's men briefly threatened an upset after taking a first half lead, but the Blue Square Premier leaders showed their quality as they recovered to win 4-1.
The Whites started well and went in front on 27 minutes when Jon Wallis worked himself some space and crossed for Shaun Welford to head in at the far post.
But the lead lasted just seven minutes as Tim Sills was on hand to score after Dover had failed to clear their lines.
Stevenage were ahead by half-time after Chris Beardsley capitalised on a missed defensive header from Olly Schulz to fire high into the net from close range.
The hosts extended their lead in the 52nd minute when Mitchell Cole pulled the ball back to Michael Bostwick after a fine run down the left and Bostwick made no mistake to finish beyond Lee Hook.
Adam Birchall was unfortunate not to pull a goal back for Dover 12 minutes from time when he saw his shot tipped onto the post.
Dean Hill converted a tap-in to add extra gloss to the scoreline for Stevenage in stoppage time.