The blow Lewis Hamilton suffered to his title hopes in Sunday's Malaysian Grand Prix will only make him more determined to win, says Nico Rosberg.
The German took a 23-point lead after his Mercedes team-mate was forced to retire in Sepang with engine failure.
"I know when Lewis has difficulties like that, he will come back fully motivated," the German said.
"So it's not very encouraging to know he's going to come back as strong as ever."
Mercedes are running the engines of all four of their teams more conservatively at this weekend's Japanese Grand Prix as a result of Hamilton's fiery failure while he was leading in Malaysia.
The team said on Thursday that Hamilton's engine suffered a big-end failure without warning, preceded by a loss of oil pressure at the last corner of the previous lap.
Rosberg said he was "not worried" that a similar problem could affect him and ultimately decide the championship, while he added that the engine changes for this weekend would not compromise performance.
All four Mercedes-powered teams will run with what are being described as "revised performance parameters".
These include, but are not limited to, a more conservative oil specification.
And a planned upgrade for the three customer teams - Force India, Williams and Manor - has been delayed so the team can learn more about Hamilton's engine as it is stripped down back at the factory in the UK and incorporate any subsequent modifications in future engines.
Hamilton was poised to retake the championship lead from Rosberg when his race was cut short in Sepang.
It was the latest in a series of engine failures that have hit Hamilton this year and affected his title campaign.
Instead, Rosberg now has a 23-point advantage with a maximum of 125 points still available.
Mercedes F1 team boss Toto Wolff said: "There is no rational explanation or pattern in these failure. If there were, we would resolve it."
Wolff said the team had spoken to Hamilton about the issue, adding: "We are feeling his pain, too.
"Despite his frustration, he has been trying to pick the team up and we admire him even more than ever for that."
Mercedes executive director (technical) Paddy Lowe added: "Malaysia was a bitter pill to swallow. We let Lewis down in a big way.
"We are continuing to investigate the issue with his engine and are doing everything we can to ensure that it is first understood and then contained for the remainder of the season."
Hamilton said: "There's no use dwelling on these things. That's just negative energy. All I can do is focus on the next race, taking things one step at a time and doing the best job we can.
"It's not the lowest point I've had. There have been lower moments, for sure."
Hamilton was in monosyllabic form in the official pre-race drivers' news conference, spending much of his time posting pictures of himself and fellow panellist Carlos Sainz doctored with cartoon rabbit features on a social media outlet.
Having been questioned about playing with his phone during the news conference, he later wrote on Twitter: "Today was meant to be fun, not at all disrespectful. Some people take themselves too seriously. I had a blast, highlight of my day."
But he told BBC Sport: "I'll try and take the positives from [Malaysia] and move on. There are a lot of positives to take from it, particularly the performance we had - try to carry that into this weekend and apply it double-time."
He said the team had told him they would "just do everything they can to make sure it doesn't happen, but that's the same thing all year long".
"They can only do what they are capable of doing. These things, weird things, have been happening. They just pop up. It's not like the same things happening all the time.
"The bottom end of the engine went and we have not seen that before, or at least not on the track."
The Japanese Grand Prix, at the challenging Suzuka track, is expected to be affected by intermittent wet weather in the wake of Typhoon Chaba.