Trailing 1-0 at half time, Lee Boon grabbed an equaliser three minutes after the break to earn a point.
The Yellamen made up for their disappointing results recently and more than matched the league leaders.
Marlow went in front on 38 mins, somewhat against the run of play, when a left wing cross was blocked but the spinning ball fell kindly to a Marlow forward.
Ascot came flying out in the second half and with only three minutes played, Lee Boon won the ball and ran at the heart of the Marlow defence and unleashed a great shot past the keeper.
On 60 minutes, there was a real let off for Ascot when a Marlow forward skied the ball over the bar in the six yard box.
Jon Bennett replaced Ben Knight and within minutes he had hit the bar from a Dave Hoar cross. Hoar then pounced on a Marlow defensive mistake, but his low short was blocked by the keeper.
Marlow also created a couple of good chances as the game swung from end to end, but it ended in an excellent 1-1 draw.
Elsewhere, Wokingham & Emmbrook extended their unbeaten run to 11 with a come-from-behind 2-1 win over Newbury thanks to goals from Sam Duffelen and Dean Thomas.
Meanwhile, Sandhurst lost a nine-goal thriller to Aylesbury United in the second round of the Berks & Bucks Senior Trophy.
The Fizzers went 2-0 down but Matt Day pulled it back to 2-2 on the stroke of half time, and the striker then added a third on 58 minutes.
However, they could not hang on for long and shipped four more in a 6-3 defeat.
A much-changed Eversley & California were narrowly beaten 1-0 by Fleet Spurs in round two of the Hampshire Senior Cup.