After weeks of negotiations, Ricciardo was expected to sign a new contract with all the Milton Keynes-based team shortly following the Hungarian Grand Prix by the close of July.
Nevertheless, the Australian opted instead to join Renault and caught Horner and RedBull motor sport boss Helmut Marko by surprise when he advised them of his choice.
“We looked over it and I think we did everything that we could to retain him,” Horner told Motorsport.com.
“He actually said that — he’d the classic break-up [line] — it perhaps not you, it’s me! And I presume he only wanted to take on a new challenge.
“I presume he was also probably concerned about his value with all the evolution of Max [Verstappen], and was probably uncertain about Honda at the time. Afterward he’s discovered that which we were speaking about beginning ahead to fruition.
“You always have a Plan B. I think once we knew he was acute, that was his mindset, so it was a really easy choice to arrive at about Pierre Gasly. ”
Horner insists however that RedBull have not improved Verstappen over Ricciardo.
“the amount 1 driver within this team could be that the driver who is ahead on the trail,” he said.
“And there is absolutely no favouritism in how people operate the team, from 1 driver to the other. Daniel will inform you very publicly.
“Mexico has been the first time that Daniel outqualified Max since Monaco. Max’s qualifying performances are huge, and that was probably part of Daniel’s decision carrying for future years. ”
Horner also confessed that Ricciardo had suffered quite a frustrating time with reliability problems, with eight non-scores around the course of 2018 causing him to jump to sixth in the points.
He’s had to handle Max’s continuing growth, and while problems have happened to either drivers, so they’Id tended to have already been Daniel to a Sunday instead of Max.
“The clutch bearing that Daniel had neglect in Sunday in Mexico, Max had on Friday. Used in Brazil Max’s petroleum tower developed a leak and also a crack that was there in Mexico, and thankfully it didn’t even block the vehicle there.
“yet 12 months ago Max was having that awful fortune. ”
Daniel Ricciardo, RedBull Racing RB14, climbs from his car after stopping on course
Photo by: Glenn Dunbar / / LAT Images