But Verstappen has made huge strides in the second half of the campaign, and last weekend charged flawlessly through the field in the US Grand Prix at Austin from 18th on the grid to finish second.
Ricciardo, 29, retired while running fourth in the race when his vehicle shut down just eight laps into the event.
F1 NICE guy Daniel Ricciardo suffered his seventh retirement of the season at the US Grand Prix at the weekend - and took out his frustrations by punching a wall, his boss has admitted.
"I'm sure he'll be having a word with his future employers about it, " said Horner, having revealed that following his early retirement from the race the Australian had punched a hole in the wall of his room in the Red Bull unit.
"It looks like the identical power issue from Bahrain. It was a throttle linkage in Japan, a battery here, it's hugely frustrating for him".
To add to his disappointment, Ricciardo's team-mate Max Verstappen went on to finish second and just behind race-winner Kimi Raikkonen.
"Hopefully we've got enough components in our [engine] pool for him not to take a penalty [next weekend in Mexico]".
"There must be frustrations obviously within him, with the issues that are happening he's knows it's not the team issue, he knows it's nothing that we've done and he can't get his head around why it keeps happening to him".
"I think really since Montreal (in June), he has driven some brilliant races", Horner told Autosport.
Ricciardo has two victories this season, last winning in Monaco, but hasn't stepped on the podium apart from that. "That Ferrari and Mercedes will not be able to run their high power modes, that is what helped us previous year".
"We are hoping that with the altitude of Mexico that it will concertina the engines a bit", said Horner.
"I want to be able to celebrate with the team at least one more time and be on the podium to enjoy that feeling, but we're running out of races which is pretty tough to take at the moment".