Christian Horner has revealed that Red Bull's engineers had to undo some "bad habits" picked by Daniel Ricciardo during his time away from the Milton Keynes-based outfit.
Ricciardo left his plum seat at Red Bull at the end of the 2018 season to join Renault for which he raced for two seasons before joining McLaren in 2021.
The Aussie's tenure with team papaya was a complicated affair, marked by his inability to fully adapt to the outfit's designs and to the handling characteristics of the latter.
Despite delivering a remarkable win to McLaren at Monza in 2021, Ricciardo was consistently outpaced by his younger and less experienced teammate Lando Norris.
In the end, team and driver opted to part ways a year before the expiration of Ricciardo's lavish contract with the Woking-based outfit.
Ricciardo was subsequently signed up by Red Bull as a reserve driver for 2023 and entrusted with simulator and development work.
But during his initial runs in the team's sim, it quickly became clear that the 34-year-old was not the same driver who was previously known to Red Bull.
"I think he picked up a lot of bad habits," Horner explained, quoted by Speedcafe.
"It took some of his old engineering team to unpick some of those and very quickly, in a virtual world, got back to where we expected – and on par – with what we were used to.
"Then, we just wanted to verify that in the real world and the tyre test provided that opportunity."
Indeed, a Pirelli tyre test conducted by Riccardo at Silverstone with Red Bull's dominant RB19 alleviated any concerns the team may have had, which paved the way for the Aussie's return to the track in Hungary with AlphaTauri.
"I think the problem is that when you’re driving cars that are difficult, it’s sometimes a compromise to get the most out of them," added Horner, expanding on Ricciardo's "bad habits".
"I mean, his whole braking technique had changed dramatically from the technique that we were accustomed to.
"He was trying to put a sticking plaster on a weakness of the car to get it to rotate. I think once we don’t pick that then you saw everything starts to become more natural."
Despite not racing for the better part of seven months, Ricciardo was in better physical shape upon his return than he had been a year before.
"He’s in great shape," the Red Bull Racing boss said. "He’s always taking care of himself.
"If anything, when he came back, he looked like he hadn’t eaten for three months. But he’s in good shape.
"He did well over 100 laps, I think at Silverstone, which is a demanding physical circuit and then to jump in at Hungary, one of the most demanding tracks on the calendar and put in a stint like he did on the medium tyre, was hugely impressive."
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