Bradford City boss Mark Hughes left 'perplexed' despite a much-needed League Two win at Mansfield Town
City were good value for a 2-0 lead given to them by goals from captain Richie Smallwood and top-scorer Andy Cook, but the narrative changed when Platt received his second caution after a slight tangle with Stags player George Lapslie with the visiting player then kicking the ball away in frustration.
Mansfield pulled a goal back soon after through Will Swan and piled on the pressure with their numerical advantage, but City held out in the face of fierce home pressure.
They are fifth in the table and two points behind the automatic promotion positions after the win.
Hughes, whose side triumphed for the first time in six matches in all competitions, said: "I'm not sure anybody understood why he deemed it fit to give Matty Platt two yellow cards.
"It completely changed the game because we were in total control.
"It just put us on the back foot, because we didn't see it coming and didn't understand why it had happened.
"We conceded almost immediately after the red card, I think because we were still a bit in shock from the referee's decision.
"But from that point onwards, we understood what was needed to protect the result that we certainly deserved.
"We dug in and everyone played a part, the lads who were subbed off late on did a shift, and the ones who came on understood they needed to get up to speed quickly to make sure we kept the opposition out.
"Even though we were down to 10 men they didn't create a great deal, because we got our shape and desire right, and we were a threat going the other way at times.
"Credit to the players, I was really proud of them, and I was proud of the response from the fans too."
City return to League Two action on Saturday when they make the long away trip to Sutton.