Leader Perez and his Red Bull team-mate Verstappen were pushing hard in the final laps of the Jeddah race, with the Mexican successfully maintaining the gap.
However, Verstappen heard a strange noise which led to the team to study the data for signs of a possible repeat of the Dutchman’s driveshaft failure in qualifying, while Perez was worried about a long brake pedal. It was at this point, having been told to moderate his pace, Perez was keen to find out if Verstappen was doing the same.
Eventually the team gave the go-ahead for both drivers to continue to push, before they managed the pace once again when it became clear that Verstappen could not catch Perez. However, Verstappen then successfully took the fastest lap point from his team-mate on the final lap.
"Once we got to the last five laps, and it was clear that Max wasn't going to catch, then they came out of it and drove to a lap time," said Horner.
"I think the biggest point of concern for us during the grand prix was when Max radioed in with about 15 laps to go saying he heard a high-pitched noise at high speed, and so your heart immediately sinks, thinking about the driveshaft failure of yesterday.
"But checking all the data that we have here, everything that they could see back in Milton Keynes. All the parameters we had looked okay. And obviously, then they pushed on again."
Regarding the request from the pitwall for Perez to lap in "target plus 0.4s," Horner explained: "It was when we thought that we had the issue with the driveshaft, so it was a matter of just trying to build in a little bit of margin."
It was at that stage that Perez asked if Verstappen was doing the same, adding that the drivers were "pushing for no reason" given the reliability worries. Horner said he understood why Perez would be concerned.
"There's always going to be that when you're the lead car," he said. "You always want to know that the tail car has hit the target first. So that's entirely normal. I think for us as a team, we were concerned about if there was a reliability issue, how do we manage that?
"Once we saw there was no issue in the data, it was a question of letting them get on with it, and then basically both managing the last five laps."
He made it clear that the drivers were free to race: "The only debates about managing the pace was when the issue with the driveshaft became prevalent.
"At that point think okay, let's turn down both cars. But as soon as it became clear that we couldn't see anything in the data, we released the cars again."
Horner said the team was happy to let Verstappen push for the fastest lap at the end of the race.
"I think we came to the conclusion that you know what, it's the last lap. If he's going to go, he's going to go. I think he'd already come to that conclusion himself. Both drivers had the info. Checo had the fastest lap at that point, he asked what it was.
"It was obvious why he was asking. He knew that Max was going to have a crack at it. Checo gave it up after the first couple of turns, he was already a tenth and a half down, and then you saw him back out of it.
"I think that you pass the message on to the driver, of course the team's interest is to maximise the points and at whatever point you feel that you may have a reliability issue then you obviously manage that.
"I think inevitably Max said on the radio the point for the fastest lap meant a great deal to him and there was no reason for us not to let either he or Checo have a crack at it."
