Red Bull losing 'best overtaker' in Formula 1 in Daniel Ricciardo

To mark Ricciardo's last outing for Red Bull before he leaves for Renault in last Sunday's Abu Dhabi Grand Prix, the team held a guard of honour for him as he walked from the team hospitality building to the garage before the race.

On the slowing down lap Horner paid him a heartfelt tribute on the radio, with an emphasis on the seven victories and "good times" that they shared.

Ricciardo has developed a reputation as one of F1's hardest racers in his time at Red Bull, earning many of his victories with charges through the field on alternative strategies or in adversity.

Horner admitted it was ironic that Ricciardo's racing ability had been a concern when Red Bull was trying to decide who to replace the retiring Mark Webber with for 2014.

"He's been a pleasure to have in the team the last five years," said Horner when asked about his farewell message to Ricciardo by Autosport.

"He's been with Red Bull since 2007, and it's been great to see him grow and evolve.

"Ironically, when we were first faced with the dilemma of who do we replace Mark Webber with, there was Jean-Eric Vergne, there was Daniel Ricciardo and there was Kimi Raikkonen.

"And our biggest concern about Daniel wasn't his pace, it was we hadn't seen him race wheel-to-wheel while he was in a Toro Rosso.

"And ever since he got in a Red Bull Racing car he's done nothing but overtake, and arguably has become the best overtaker in the business.

"He's driven some fantastic races for us."

Ricciardo had been backed by Red Bull through his junior single-seater career, and it initially brought him into F1 with HRT in mid-2011 before giving him two seasons at Toro Rosso.

He admitted ahead of Abu Dhabi that leaving the Red Bull family was extremely emotional, but was a change he felt he had to make because he "needed to go it alone and make my own decision. I had to take this step to try to be the best version of me."

Horner said Ricciardo had been an ideal Red Bull driver.

"His personality has been a tremendous fit with the brand," he said.

"His energy in the team has been hugely popular, the dynamics with him and Max [Verstappen], you've only got to look at the mischief that they get up to - it's been great."