Ricciardo, victor of the Chinese Grand Prix two weeks ago, and Verstappen were given a rebuke by the stewards and both apologized for a costly smash, which Horner said they were both to blame for.
Stewards confirmed that both drivers expressed regret about the collision, with Verstappen and Ricciardo having already issued separate apologies to Red Bull in TV interviews. "The driver [Verstappen] of vehicle 33 made two moves, both of which were relatively minor", the stewards said.
"The driver of vehicle 3 [Ricciardo] admitted he left his move to overtake on the left, too late".
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Enough is enough for the boss of Red Bull's Formula One team.
He added: "We have discussed it at length on many, many occasions, and even this morning, that we wanted to avoid a repeat of Force India's scenario from past year".
"I have watched a few replays and the only thing we can both say is sorry to the team..." We tried to keep it clean and give each other room but we were racing hard and in the end it cost us.
'This was the worst-case scenario and everyone is pretty heartbroken'.
"...it's more just about saying sorry to the team", Ricciardo said, "just apologise the best way we can".
But after their pit-stops, Verstappen managed to get the jump of the Chinese GP victor, and as the pair raced towards Turn 1 on lap 40, disaster struck.
The inevitable conclusion to Daniel Ricciardo and Max Verstappen's escalating on-track hostility was clear to all but those who could have stopped it from happening.
"But they are both in the dog house". It is the last thing we wanted.
"Unfortunately, today has happened and there is no blame apportioned to either side". They've been reminded that they are part of a team and that they have a responsibility in the role that they perform, that they're both highly paid individuals to act with the team's interest at heart and not just their own - and the message was delivered very clearly.
Red Bull now trail leaders Ferrari by 59 points in the Constructors' Championship, while lead points scorer Ricciardo is 33 points behind Lewis Hamilton, the race victor, in the Drivers' Championship.
"It was a racing accident between the two, there was not more fault for one or the other".
As for the crash, the 20-year-old said he is not listening much to all the post-mortems in the media.
It came among a series of dives as master overtaken Ricciardo tried desperately to round up master defender Verstappen. "If you move on him all the time where can the poor guy go?" he said.
However, their last battle ended in tears as Ricciardo went to pass Verstappen, the Dutchman blocked, and Ricciardo crashed into the rear of the sister Red Bull.