As Sebastian Vettel suffered yet another engine related issue that put him out of a grand prix, Christian Horner has slated Renault.
Sunday's Austrian Grand Prix, which took place at Red Bull's home track in Spielberg, yielded yet another wretched performance as not only did they lack the power needed to fight at the front but Vettel retired for the third time this season.
The reigning World Champion lost drive at the start of the grand prix and although his RB10 got going again, he was a lap down in 22nd place.
Involved in an incident later with Esteban Gutierrez, Red Bull opted to retire Vettel's RB10 to "save some mileage."
Horner said: "It's frustrating we're in the situation we are.
"We've obviously had a lot of success with Renault. We've won all our races and Championships with them, but the situation isn't improving at the moment.
"The reliability is unacceptable. The performance is unacceptable.
"There needs to be change at Renault. It can't continue like this. It's not good for Renault and not good for Red Bull.
"We need to work together as partners because there will not be another engine in the back of the car next year, but we want to be competitive and we want to run at the front."
Asked what changes he wanted to see, the Red Bull team boss said: "Something needs to happen because whatever's being done there at the moment isn't working.
"It's not our business, not our responsibility. We're the end user and it's just frustrating it's not where it needs to be."
The latest Renault reliability issue comes at a bad time for the French engine manufacturer as earlier in the weekend Red Bull revealed that they could consider building their own engines.
The team, though, will definitely be sticking with Renault for next season.
"A team like Red Bull isn't short of choices, but we want to make sure we're competitive for the long term," Horner said.
"Obviously designing and manufacturing our own engine isn't currently part of that plan."
Any reproduction, publication or redistribution of this material without the written agreement of 365 Media Group is strictly forbidden.