Toto Wolff saw cause for concern in Abu Dhabi Grand Prix qualifying on Saturday but is backing Lewis Hamilton to muster an "angry" response in the decisive season-ending race.
Max Verstappen beat title rival Hamilton to pole position by 0.371 seconds with a flying lap that gives him a clear view of his first Formula One world championship.
Verstappen and Hamilton enter Sunday's race tied on 369.5 points, just the second ever example of the top two in F1 heading into the finale all square.
Red Bull's Verstappen already has a slender advantage due to his superior win tally – a potential tie-breaker – and will now lead Hamilton off the start line, prompting Mercedes team principal Wolff to acknowledge to Sky Sports: "It's 1-0 for them."
Verstappen will also start on a soft tyre that should initially work in his favour, potentially leaving Hamilton – on mediums – battling the chasing pack.
"I am also worried for tomorrow because their long runs were much better on Friday," Wolff said. "Our tyres were just not in the window they were.
"You can see Q1, Q2 was ours. It looked like a pretty easy run, and then you lose all the performance.
"The pace was there. Obviously on the long runs you do not know. The car that's faster tomorrow will win the race, irrespective of who starts on which tyre."
Wolff added: "This is a long race, and it's Lewis Hamilton in the car."
Indeed, Hamilton is not lacking motivation as he pursues a record-breaking eighth championship.
"He's hunting," his boss said. "I think there is nothing you need to say. I think he's going to be angry and that's good, motivated for tomorrow to hunt him down.
"We are on the back foot. Sometimes you need to see the positive, sometimes that's not bad as a starting point."
Sergio Perez gave Red Bull team-mate Verstappen a tow to boost his pole bid, although chief Christian Horner pointed out his main man had enough pace regardless.
"I think that's one of Max's best laps of the year," Horner said. "Even on the following lap that we got him to back off on, he matched the time. The tow was probably worth a tenth or two, not half a second.
"His last sector, when you look at the level of downforce he's got on, is insane, absolutely insane."
Horner, who was "surprised" Hamilton stayed on the mediums, added: "I think that Max is giving it everything. He's driving his heart out. He's thrown everything at this session."