Freddie Ladapo’s 11th-minute goal has given the Blues a 1-0 half-time lead at Exeter City.
Cameron Burgess returned to the Town line-up on the left of the defence with George Edmundson dropping to the bench, while the Blues XI was otherwise unchanged. Gassan Ahadme was back among the subs having recovered from his foot injury.
Exeter made one change with an extra midfielder, Harry Kite, coming into the team for forward Matt Jay, who dropped to the bench.
On-loan Town midfielder Rekeem Harper was ineligible and watching from the sidelines, laughing that he was "a neutral” when asked which side he was supporting.
The Grecians saw most of the ball in the early stages but without threatening. On seven, Leif Davis won a corner on the left from which Conor Chaplin mistimed his header and the ball looped well over.
Town began to take control and in the 10th minute Chaplin crossed from the right and Harness flicked goalwards, however, keeper Jamal Blackman was able to block.
But a minute later, the Blues were in front. Skipper Sam Morsy chipped a ball into the box towards Harness, who nodded down to Ladapo and the one-time Plymouth striker stooped to nod his ninth goal of the season - and his fifth in five games - into the net.
Town went looking for a second, putting the Grecians under significant pressure in the minutes after their goal and on 20 a Harness shot from the edge of the box looped behind for a corner.
However, the home side withstood the brief storm and in the 22nd minute forced Blues keeper Christian Walton into his first save of the afternoon.
A corner from the right was nodded back in by Tim Dieng and Alex Hartridge hooked an effort at goal from close range which Walton bundled wide of the post.
Five minutes later, Jack Sparkes blazed over from 25 yards after another corner had been worked short to him.
With neither side having carved out a chance with the game going through a flat spell, Cameron Humphreys required treatment in the 38th minute but fortunately was able to continue.
As the half moved into injury time, Burns was tripped as he burst away on the right and Sparkes was shown the game’s first yellow card.
Davis hit a low shot from the free-kick towards the near post which got stuck under a defender’s feet before being cleared.
That was the final action of the half with the Blues deserving their lead at the break, although without dominating in the manner of many of their games this season.
Exeter had started well but Town had started to get on top when they scored their well-worked goal. The Blues threatened a second in the spell immediately after the goal but without causing Blackman much more trouble before the game went through a flat period towards the break.
Town keeper Walton was forced into one save but otherwise had had a quiet first period, although with the Grecians having made headway down the right on a couple of occasions.
Exeter: Blackman, Key, Sweeney (c), Hartridge, Caprice, Collins, Dieng, Kite, Sparkes, Brown, Stansfield. Subs: Lee, Grounds, Diabate, Beardmore, Chauke, Jay, Nombe.
Town: Walton, Donacien, Woolfenden, Burgess, Burns, Humphreys, Morsy (c), Davis, Chaplin, Harness, Ladapo. Subs: Hladky, Edmundson, Vincent-Young, Camara, Edwards, Ahadme, Jackson. Referee: Alan Young (Cambridgeshire).