Blues made hard work of overcoming the opposition after taking an early lead through youngster Olly Miles and been well on top in the first half-hour.
The hosts’ squad for the tie comprised the same 16 that had taken the points at Margate a few days earlier but all the substitutes there were in the starting 11 against Baldock. Both Jamie Cureton and Jack Thomas were on the bench but didn’t come on during the tie.
The Blues made an excellent start and went a goal up in the third minute. A corner was cleared but when the ball came back out to Jordan Wescott the midfielder crossed into the box where Miles netted his first goal with a glancing header inside the far post.
There was then a sequence of near misses for Stortford as Nick Brown and Miles almost added further goals before, in the 19th minute, Miles and Brown linked to provide Luke Callander with a chance but the striker’s shot looped over the bar.
Miles was close again on two further occasions by the half-hour but the visitors were gradually working themselves back into the contest and Calum Kitscha pulled off a fine save to keep out a shot from Russell Bull after Charlie Joy crossed from the left in the 39th minute.
Stortford got off to a sloppy start to the second half with a cross-cum-shot from the right by Owen Robertson being stopped by Kitscha but then spinning up and deflecting against the near upright.
Baldock came close again as Kieran Barnes’ angled shot from the left drifted past the far post in the 66th minute. Callander headed wide of the target from a cross from substitute Johnville Renee in the 73rd minute whilst there was another escape for the Blues soon afterwards when Isaac Nkosi sliced a clearance that allowed Alfie Barker to advance clear on goal. The substitute lobbed the ball over Kitscha but fortunately Chris Gregan was on hand to clear the ball off the goal-line.
Then in the 78th minute, in their next attack Stortford netted the winner with Ben Sampayo crossing from the right and Callander planting a header into the bottom corner.
Five minutes later Baldock stopper Jack Farmer saved well from Sampayo at the expense of a corner and then from Alfie Mason’s corner a near post glancing header by Callander was a foot over the bar.
Stortford safely negotiated the remaining minutes and will travel to either Watford or Leverstock Green in the last eight.
STORTFORD: Calum Kitscha; Ben Sampayo; Chris Gregan; Hector Kyprianou; Sam Robbins; Isaac Nkosi; Alfie Mason; Jordan Wescott (Ryan Charles 76); Olly Miles; Luke Callander (Ryan Henshaw 85); Nick Brown (Johnville Renee 63). Unused substitutes: Jack Thomas and Jamie Cureton.
BALDOCK TOWN: Jack Farmer; Stephen Brooks; Josh Furness; Kieran Barnes; Dean Gilbert; Harry Holland (Daril Ngwala 88); Charlie Joy (Alfie Barker 71); Lewis Barker; Russell Bull; Kim Forsythe (Sam James 46); Owen Robertson.
Unused substitutes: Luke Gregson and Adam Harpur.
Referee: Stuart Cheek