Lewis Hamilton was thrilled to split the Ferraris and claim second place on the grid for the Russian Grand Prix, describing the Italian team as having a "jet mode" on the straights.
Mercedes are looking to avoid going a fourth straight race without winning for the first time in the hybrid era at a Sochi circuit where they have never been beaten before in Formula One.
Leclerc was over four tenths clear of Hamilton in qualifying on Saturday, however, the Monegasque claiming his fourth consecutive pole, albeit five-time world champion and 2019 standings leader Hamilton was happy to put his car right in the mix by pipping Sebastian Vettel.
"I'm so glad it came together - I wasn't expecting to get on the front row, that's for sure," said Hamilton.
"I'm really, really happy with it. It was a tough qualifying session because these guys [Ferrari] have some crazy speeds on the straights.
"They go to another level. That party mode you spoke about us having, they have something else beyond that - jet mode.
"I gave it absolutely everything I had at the end. It's been a good weekend. We've just continued to work and improve the car - the team's done a fantastic job in trying to understand and trying to progress.
"You finish the lap which felt great and then obviously you see we have that [four-tenths] deficit to them still, but to split the Ferraris is always a good scenario for us.
"It's kind of cool, you've got to be happy with a performance like that from the team. It could be a lot worse and I look forward to the fight."
— Mercedes-AMG F1 (@MercedesAMGF1) 28 September 2019
Mercedes hope a surprise strategy move could play in their favour on Sunday, as they will start on the slower but more durable medium tyre, compared to Ferrari being on softs.
"We were fortunate enough to opt for a different strategy," said Hamilton. "They have that power, so we have got to try something.
"It's a long way down to turn one, which is not always the best for starts when we are on the harder tyre, but I'm going to try and tow the life out of Charles if I get the chance. He's stealing all the poles right now!"
Valtteri Bottas qualified fifth after aborting his second flying lap in Q3 but will start fourth due to a grid penalty for Red Bull's Max Verstappen.
Mercedes team boss Toto Wolff added: "I'm really happy for the team. Lewis extracted everything from the lap. It's a shame for Valtteri because he was on a good lap too before he aborted.
"The engineering team really made the most of the package this weekend but against seven, eight tenths on the straight there is only so much you can do against that.
"That's quite a massive amount. We have had many good seasons and many great races and now we have another challenge on our hands to fight.
"We'll be on a harder tyre to everyone around us which will make the start a little bit tricky but will hopefully create some opportunities later in the race."