Having beaten Brackley 3-1 at Latimer Park on January 2, the Poppies were unable to repeat the trick nine days later as the Saints clinched a 1-0 victory at St James Park to extend their lead at the top to five points.
Both teams were hampered by illness and injury with Brackley naming just three substitutes and Kettering four while the Poppies were missing key players including Jordon Crawford and Connor Barrett.
Nonetheless, there was a welcome return to the starting line-up for Riccardo Calder after a lengthy spell on the sidelines.
And Cox found it hard to pick fault with his team’s efforts in a narrow encounter of few chances, which was decided by Lee Ndlovu’s goal five minutes before half-time.
“I think you have to give credit to both sides because Brackley were very depleted as well so both clubs, for the league, have put on a fixture,” Poppies boss Cox said.
“I am delighted with us. We lacked a bit of quality at times and we had some big players missing with illness and injury but we put a side out there and we were competitive.
“I think Brackley have scored with their only real chance and we have got into the final third and had chances to score goals and haven’t.
“We are down to the bare bones but I thought the lads were superb. They worked really hard, I don’t think the large number of fans who travelled are disappointed with us, it’s just the wrong result at the end of the day.
“We lacked that little bit of extra polish and it was a frustrating night.
“A draw probably would have been a fair result if we’d put our big chance away but we didn’t and Brackley are top of the league for a reason and they made us pay for it.”
Cox, meanwhile, questioned whether the “integrity” of fixtures is at stake with teams currently having to field depleted squads to get matches played as the Covid-19 pandemic continues to bite.
“We are told to play games and we have played one,” he added.
“But I think everyone needs to look at the integrity of the fixtures and this match, like every other, deserves to have two full squads and I think the fans deserve that.
“I’m not playing the game down. I thought the two sides worked really hard but, if you look at both benches, both teams are depleted and it probably hit us more in terms of key players when you look at the form lads like Jordon Crawford and Connor Barrett have been in.
“If you lose quality players from any team in any league it’s going to affect you.
“The question has got to be answered by the league. There are a lot of people who don’t understand what is happening at the minute and maybe they need to answer that.
“Both clubs have put out competitive sides and have tried to win and I think both sets of fans applaud that.
“That’s all we can do, show that bit of desire to get the games played.”