"When you consider where we were pre-season to where we are now, that's a pretty long way in a couple of months," said Red Bull boss Christian Horner in Monaco.
"Hopefully if we can keep it up we'll be able to challenge Mercedes before too long in the future," he added.
However, it is a markedly different story for Mercedes' other big-budget rivals.
Wolff admits he has been surprised in 2014.
"I'm surprised that McLaren have not pushed us more because they have the same power unit," he is quoted by the Guardian.
"They looked very strong in the first test in Jerez, but they haven't been able to deliver on track. Looking from where we are it looks as if they have gone backwards," said Wolff.
As for Ferrari, Wolff admitted he is even more surprised by the fabled Italian team's struggles.
"It is bizarre their engine didn't perform in the way ours did," he said. "And they haven't been able to integrate the different parts of the car in the way that we did."
"So it's down to the people, down to the skill and how you apply those budgets.
"It's the skill of a team, it's the skill of the drivers, it's the skill of a company how it's applying those resources to achieve the results," he added.
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