There was little to choose between the sides in the first half, though Slough had the better chances and were disappointed not to take a lead into the half-time break.
Slough went close as Murphy whipped a great ball across which Sinclair headed down into the turf and over the angle of post and bar.
Alex Brown headed a corner over under pressure from goalkeeper Sam Leggett, but at the other end a dangerous ball across goal forced Dave Woozley to slide in and clear over his own bar.
However, Slough went closer still as the ball was worked right to Sonner, who played a well-weighted ball across the face of the six yard box, only for a defender to poke it away before Burnell could get a touch.
The game continued to be a tight affair in the second half, with Biggleswade’s Craig Daniel seeing a shot well smothered by Warrington and cleared away from danger.
Burnell went agonisingly close to making contact to a whipped corner, but the hosts could have taken the lead when Ashley Fuller almost scored direct from a whipped cross, with any touch certain to have taken the ball beyond Warrington.
It looked as if Slough were tiring as the Rebels were seeing less and less of the ball, but with thirteen minutes remaining, and slightly against the run of play, Slough were awarded a penalty. A corner had caused confusion in the Waders’ box, and, after a shot had been cleared off the line, the hosts were penalised for a high foot on Sean Sonner, referee Platt pointing to the spot.
Burnell stepped up confidently and made no mistake, firing into the bottom corner for his 13th goal of the season.
Just a minute later, Burnell had a glorious chance to double the lead after some neat build-up play had led to a cross into the middle, which the striker could only volley straight at Leggett.
Biggleswade then broke instantly, and the ball bounced around and fell to Alex O’Brien, who placed a shot into the bottom corner from the edge of the box.
Slough pressed hard for a winning goal towards the end, and went close as Murphy fired wide from 30 yards – but neither side will be too disappointed with a point on the balance of play.
Biggleswade Town Line up
Sam Leggett, Tom McGowan, Darryl Coakley, Peter Gatti (c), Bradley Hewitt, Scott Field, Craig Daniel (Mitchell Cole), Craig Rydeheard, Alex O'Brien, Brett Donnelly (Paul Barnes), Ashley Fuller. Subs not used: Stuart Lochhead, Jon Woolf, Paul Reynolds.