SPA-FRANCORCHAMPS, Belgium — Although weighing up the decision to leave Red Bull gave Daniel Ricciardo "a few sleepless nights," he felt his unexpected move to join Renault was inevitable.

The Australian driver stunned F1 when, instead of signing a new deal with Red Bull on July 31 as widely anticipated, he announced days later he was joining Renault from 2019.

Not, he said, because of an uneasy relationship with Dutch driver and teammate Max Verstappen. Ricciardo insists there was "no falling out or bad blood" with Verstappen, team principal Christian Horner or any of the management.

His decision to leave was because he needed "fresh motivation" after feeling "frustrated and a bit numb" following so many years within Red Bull's set up. Ricciardo started in F1 with Toro Rosso — Red Bull's feeder team — in 2012 and joined Red Bull in 2014.

"I was really torn with what to do and that process took time," Ricciardo said Thursday. "It wasn't easy. There were a lot of factors and variables in my mind. When I weighed it up the change of setting, a new challenge, are probably the answers I needed."

Ricciardo began this season well, winning two of the first six races.

Then, the team's reliability problems resurfaced as did his sometimes difficult relationship with Verstappen. At the Azerbaijan Grand Prix in April, they crashed into each other. Neither accepted the blame.

Ricciardo was faster than Verstappen in Baku but couldn't get past him. As a frustrated Ricciardo tried to force his way past, Verstappen closed the door on him and Ricciardo, with no time to react, slammed into the back of his teammate.

It wasn't the first time they had collided.

Last year, Ricciardo was livid with Verstappen after being bumped off the track by him on the first lap of the Hungarian GP. Ricciardo described Verstappen's driving as "amateur" for the way he swerved into him when going wide on the exit from a turn.

Although the 29-year-old Ricciardo has won seven races for Red Bull, Verstappen is just 20 and considered the future star of F1.

By the age of 18, Verstappen became the youngest driver to win an F1 race and qualify in the top two positions. He has already won four F1 races, secured multiple podiums, and is one of the quickest and best at overtaking.

While Red Bull has always insisted the drivers were on equal footing, Verstappen was given a lucrative multi-year deal — before Ricciardo was offered his new contract — which appeared to suggest the team's focus was more on him.

Ricciardo was asked if his move to Renault was to get away from Verstappen.

"No is the short answer," Ricciardo replied, adding that perceptions that Verstappen was the team's designated No. 1 were inaccurate, albeit understandable.

"From the outside people thought that, but hand on heart there was never any concern or sign of that," Ricciardo said.

He was also happy with the new contract offered to him by Red Bull motorsport adviser Helmut Marko but it was not enough to change his mind about leaving.

"(Marko's) known me for 10 years and I think he'd sensed at times some frustration or maybe some things changing in me," Ricciardo said. "He was a little bit disappointed I was moving on."

Ricciardo's sudden refusal of a new deal left Red Bull scrambling for a new driver for next season.

The seat has gone to 22-year-old Frenchman Pierre Gasly, fast-tracked from Toro Rosso after largely exceeding expectations this season.

"He owes me a drink," said a smiling Ricciardo, who sat next to Gasly at Thursday's news conference. "Two drinks."

Gasly and Verstappen are friends since their karting days but that friendship might be more difficult to maintain on the F1 track.