Mercedes chief Toto Wolff admitted that he is somewhat surprised by Red Bull's struggles during last week's Jerez test.
The reigning World Constructors' Champions struggled at the Andalucian circuit last week and completed only 21 laps over the four days of testing, struggling with overheating and engine problems throughout.
"Personally I am surprised," Wolff told Autosport.
"The problems on the first and second day were expected, but finishing the test with almost no mileage is not what I would have expected from Red Bull.
"Honestly I don't really know what has happened, I have only read the comments.
"They are a good team with a very determined approach, and they have shown in the past that they were very competitive.
"So I have no doubt that they will eventually solve those problems, whether they are on the engine or on the chassis itself."
Williams engineer Rod Nelson admitted that Renault and Red Bull's struggles at Jerez seemed serious, but added that it is far too early to write off Adrian Newey and his design team.
"Renault have got some kind of nightmare going on, but that may be one thing," he explained.
"It could be that the battery might me a bit small or overheating."
New Williams driver Felipe Massa, however, believes it would be a good thing for the sport if Red Bull continues to struggle, as it would allow other teams to challenge for the title.
"I think if you don't see the Red Bull winning all the time it can be positive for everybody," the Brazilian said.
While Massa's former team-mate Fernando Alonso claims that Ferrari have been too busy testing their own car to ponder the situation at Red Bull, but added that is certain that the Milton Keynes outfit is bound to find a solution to their problems.
"It's not our main focus with what others are doing," Alonso said.
"We have a lot of things going on inside our garage, so we are not looking too much outside.
"They [Red Bull] have done little running so far, but they will put things in place I am sure."
Any reproduction, publication or redistribution of this material without the written agreement of 365 Media Group is strictly forbidden.