An impressive comeback drive from 18th to second at last weekend's US Grand Prix registered his eighth podium of 2018 and received acclaim from Horner, who felt his performance noted the progress he'd shown during the campaign.
Ricciardo was running in fourth place when his auto lost power exiting the Turn 11 hairpin early in the race, forcing him into his seventh retirement of the season.
But since then, Daniel Ricciardo's year has morphed into a proper annus horribilis - and that's something that's troubling the Australian as he prepares for his final three races as a Red Bull driver, following his retirement from the United States Grand Prix.
"For Daniel, having started the race strongly and looking so competitive it was hugely frustrating to lose him so early on with what looks like a repeat issue of Bahrain, where the engine energy store is suspected to have failed terminally", said Horner.
Red Bull itself is parting company with Renault at the end of the season and linking up with Japanese manufacturer Honda instead.
To add to his disappointment, Ricciardo's team-mate Max Verstappen went on to finish second and just behind race-winner Kimi Raikkonen.
Rockets making renewed bid to acquire Jimmy Butler
The Rockets likely wouldn't make such an aggressive offer unless Butler agrees to sign an extension with the team beforehand. Butler can opt out of his contract and become a free agent at the end of the season.
"Thankfully we have one in more our allocation that we introduced in Sochi, meaning we should avoid a penalty in Mexico next weekend". "That Ferrari and Mercedes will not be able to run their high power modes, that is what helped us a year ago".
"It's ironic that it always happens on his vehicle", Red Bull team boss Christian Horner is quoted by German media outlet Auto Bild. "He knows we're doing everything we can, it's just one of those things". "I'm sure he'll have a few words with his future employer about it", team boss Christian Horner is quoted by Auto Bild.
"At that altitude the engines can't breathe [as easily] and it brings it all closer together, and that gives us a chance".
"Max never surprises us with how good he is", Marko said after the Dutchman finished second in Austin.
Ricciardo has two victories this season, last winning in Monaco, but hasn't stepped on the podium apart from that.