The Blues’ game at Oxford remains 0-0 at half-time, perhaps unsurprisingly with four of the last five matches - including the last three - between the teams having ended goalless.
Skipper Sam Morsy was among the Town subs, one of two changes from last week’s 0-0 home draw with Portsmouth.
Morsy, who had been forced off in the last two matches by a hamstring problem, was replaced in the centre of midfield by Tom Carroll, while Joe Pigott was the central striker with Kayden Jackson having picked up a more serious hamstring injury against Pompey.
Joining Morsy among the subs for the first time under manager McKenna was young centre-half Elkan Baggott, who was in the 20-man squad last week but without making the final 18, while U23s midfielder Cameron Humphreys made the trip the Kassam Stadium but didn’t make the matchday squad.
Janoi Donacien captained with fellow centre-half Luke Woolfenden making his 100th appearance for the Blues.
Oxford made three changes from the team which won 2-1 at Shrewsbury last week with Sam Long, Ciaron Brown and Billy Bodin in for John Mousinho, Steve Seddon and Nathan Holland, who were all on the bench.
After the two teams had taken a knee, Oxford, who had the wind in their favour, started the stronger, winning an early corner, before the Blues started to see most of the ball.
In the fifth minute, a dangerous Town free-kick from midway inside the Oxford half on the right fell to Woolfenden at the far post but the central defender’s shot was blocked by Long.
Town keeper Christian Walton was forced into his first save of the afternoon two minutes later when Gavin Whyte burst into the area and hit a low shot which the Blues’ number one stopped before Donacien turned the ball behind.
On 12, Town gave the ball away just inside their own half - although Bakinson had looked to have been fouled as he looked for a return ball - and Whyte struck another shot but too close to Walton and without any power.
A minute later, Bersant Celina latched onto Pigott’s flick then crossed from the right only just in front of Conor Chaplin.
Soon afterwards, Burns, who had already been on the end of one or two overzealous challenges, cut inside Ryan Williams and sent in a right-wing cross which home keeper Simon Eastwood palmed behind.
Oxford made heavy weather of clearing the resultant corner but the ball just wouldn’t fall for Town, who were getting on top and looking the more threatening side, although with too many wayward passes in the final third.
The home side might well have gone in front in the 27th minute when Mark Sykes’s strike from the right of the box deflected out to Williams in space to the left but the Australian international shot into the ground and wide when he ought to have done much better.
Town were continuing to see most of the ball but Oxford had another chance in the 34th minute when the ball dropped to Whyte on the edge of the box, however, the Northern Irish international volleyed well wide when it looked another decent opportunity.
Two minutes later, Burns was sent away on the right and cut back towards Celina but a defender was able to turn behind ahead of the Kosovan international.
The Welshman had been Town’s biggest threat throughout the first half and on 39 the ex-Fleetwood man went close to putting the Blues in front.
Burns brought the ball in from the right, exchanged passes with Pigott, then curled an effort with the outside of his right boot which flicked wide off Sykes at the far post. From the corner, Eastwood dropped the ball but was able to claim before a Town player was able to get onto it.
Soon after, Celina shot into the side-netting from the left but having strayed offside with Town looking increasingly dangerous.
But a minute before the whistle, Oxford striker Matty Taylor struck a low effort straight at Walton from the edge of the Town box with no further threat at either end before referee Marc Edwards ended the half.
The Blues had been in control for the most part but with Burns’s shot which was diverted wide their only really clear-cut chance.
Too many final balls or passes as they got into the final third had gone astray, while Oxford had had the half’s better opportunities without having seriously tested Walton.
Oxford: Eastwood, McNally, Long, Brown, Sykes, Kane, Brannagan (c), Williams, Bodin, Whyte, Taylor. Subs: Stevens, Mousinho, Forde, Seddon, McGuane, Holland, Winnall.
Town: Walton, Donacien (c), Woolfenden, Burgess, Burns, Bakinson, Carroll, Thompson, Chaplin, Celina, Pigott. Subs: Hladky, Baggott, Penney, Morsy, Aluko, Bonne, Norwood. Referee: Marc Edwards (Tyne and Wear).