Phil Parkinson felt City “lacked a bit of spark” as their mini unbeaten run on the road was ended by play-off chasers Swindon.
Midfielder Dean Cox broke down their defensive resistance with the only goal midway through the second half. It was the first they had conceded away from Valley Parade in four games.
The Bantams had resisted well against the seventh-placed hosts but were unable to create enough to threaten a comeback.
Parkinson was disappointed by the standard of crossing when they tried to counter-attack.
He said: “We had the chance to put balls into the box but didn’t find that quality which we’ve had in recent weeks from wide areas.
“We didn’t keep possession as well in the second half. At first, we worked our way up the pitch with the ball and we stopped doing that to an extent.
“In the first half, Swindon had a lot of possession in their own half. They moved up 20 yards in the second. You’re always going to come under pressure when that happens against good players. But they haven’t created a great deal against us.
“I thought the team defended well. When we had those moments out wide one against one, we just lacked a bit of spark for whatever reason.”
But Parkinson, who thought Stephen Darby was fouled in the build-up to the Cox goal, admitted Doyle’s absence had a big effect as Swindon took control of the game.
The City boss said: “Losing Doyley was a blow. We were compact and solid and I felt really comfortable in the first half.
“I put Mez in there because he’s played midfield quite a few times for York. But it was always going to be a tough ask of him after being out so long.
“He did fine but we lost that control of the game that Doyley gives us with the way he sits in front of the back four and keeps possession.”
Despite the loss, Parkinson praised City’s recent efforts which have assured their position in League One for another season.
He said: “We’ve come away on our travels and had some really tough games towards the end of season. I think a lot of people looked at these recent games with a bit of trepidation but, in the main, the away form has been good.”
City left out James Hanson to ease him back after his recent back and groin problems. He had played the full game in Friday’s win over Peterborough.
But he is expected to return for the final home game against Crawley on Saturday.
Adam Reach had a quiet afternoon in his last City outing but Parkinson said: “He’s done a great job for us.
“We tried him on the right because we thought he might give us a bit of joy cutting in on the left foot. It didn’t happen but he has got that flexibility to play different positions.
“But he’s been good for us and scored goals – none more important than the one the other night.”