The Silver Arrows put up a tense fight in the final edition of the Malaysia Grand Prix, but it was Red Bull's Max Verstappen who claimed top honours.
The Dutchman passed polesitter Lewis Hamilton into Turn 1 on the fourth lap and cruised to his first victory of the 2017 season. Lewis came home second - some 12s back - to score his ninth podium of the year and extend his championship lead to 34 points with five races to go.
Title rival Sebastian Vettel stormed from the back of the grid to take fourth, to limit the damage to his championship challenge.
"It was a much better weekend than we had anticipated after our Friday, considering the issues we did have with the car this is a good result," said Lewis. "But still we have a lot of work to do with the car, some of the corners really magnified the issues we have.
"These next races are going to be crucial in terms of ironing out some of the creases we have with the car. I was having some problems with de-rates at the beginning of the race, so I was struggling with battery power.
"Valtteri seemed to struggle a lot more; I was able to pull a little bit more out of it. Naturally, I wanted to win the race, winning the races is still the goal. So even to be second is not that satisfying.
"Today was a step towards in trying to win the world championship and every point counts."
A fast-starting Valtteri Bottas challenged Verstappen for second into Turn 1 on the opening lap, but the Finn was hustled down the pack by first Daniel Ricciardo, and then demoted to fifth by Sebastian Vettel during the pitstop phase. From there it was a lonely race home to fifth for a disappointed Valtteri.
"Today was difficult, I was trying everything I can, I was giving it all I had, but I was lacking pace and I was sliding around," he said.
"The start was definitely the best part of the day. It was really good, I could actually attack a little bit and fight for positions. But not long after that I just started to drop down and couldn't keep up with the others.
"In the first stint I had quite a lot of understeer, so I was struggling with the balance. The story of the race was managing the tyre temperatures. If I tried harder, then I started to overheat the tyre and slide even more, so I had to manage everything and that's why I was so slow.
"We need to analyse the race because the upgrade package should have been quite a step forward in terms of downforce, but I couldn't really see it. There are still a lot of things we need to try to understand, we need to learn from today.
"For Japan, we need to make sure we choose all the right bits for the car, and hopefully we will see some cooler temperatures."
Mercedes team boss Toto Wolff acknowledged that the two Silver Arrows were simply not fast enough in Malaysia, insisting there's still plenty more hard work to do over the remaining five races.
"It was clear after just a few laps that both Red Bull and Ferrari had better cars than us today - but we nevertheless managed to score a good number of points and extend our lead in both championships," said Toto.
"After a weekend where we have lacked a significant chunk of performance, we couldn't have imagined such a good outcome, but we can't let that distract us from the job we have in front of us.
"We leave Malaysia with a lot of question marks and we need to find answers to them in the next days and weeks, to ensure that we keep moving forward and racing at the front in the final quarter of this championship.
"We cannot get distracted by the fact we got lucky again this weekend. Lewis did a fantastic job today to score P2 while Valtteri, just like over the rest of the weekend, struggled to match that pace and brought the car home in P5.
"We know that gap doesn't reflect his true level of performance, and it will be a priority for us to put two equally competitive cars on track next weekend in Suzuka. In simple words, there is a lot more work ahead of us if we want to come out on top by Abu Dhabi."
Trackside Engineering Director Andrew Shovlin says the team heads to the Japanese Grand Prix committed to getting on top of the recent issues in Singapore and Malaysia.
"We expected a tough race today and it was," said Andrew. "We lost the lead to Verstappen very early which was frustrating, but this is a reflection on our pace today which was just not good enough.
"We had a similar story with Valtteri who made a great start and did a really good job defending against Daniel for the opening laps but ultimately couldn't hold him behind. We have benefited significantly from Ferrari's misfortunes this weekend but they had an extremely quick car and we are under no illusions that the remaining five races will present us with a tough challenge to keep our noses ahead in both titles.
"We will be working hard in the coming days to understand our deficiencies this weekend. But Suzuka is a very different type of circuit and we will go there fighting to get on top of our problems and back to the front."
With P2 and P5 Mercedes-AMG PETRONAS Motorsport (503 points) extend the lead to Ferrari (385 points) in the Constructors' Championship to 118 points.