Monza: Nico Rosberg has no intention of giving Mercedes team-mate Lewis Hamilton an easy ride to his third world title despite falling 53 points behind him in the race for this year's championship after Sunday's Italian Grand Prix.
The 30-year-old German, who retired with a blown engine with two laps remaining, had his worst day of the season as the defending two-time champion Briton drove to his 40th career win in commanding style.
"It's a fact that it's a massive step in the wrong direction," said Rosberg.
"It's the biggest loss I've had in one day throughout the whole season, so that's very bad, and I now need to catch up a few points.
Read: Nico Rosberg triumphs in Austrian Grand Prix
"I keep going. Giving up doesn't exist for me. So, I'll just keep fighting and I've got to try to win the next couple of races somehow."
Rosberg's problems began on Saturday morning when after final free practice a cooling system leak meant he had to change engines - and revert to an older unit used at last month's Belgian Grand Prix.
"The whole weekend just went completely wrong and unlucky I think," he added. "There were so many repercussions of this engine issue.
"It wasn't an engine issue, actually. It was a chassis issue that made me have to change. To have it explode two laps from the end was unbelievable. It's even more disappointing.
"I was going to have a good go at Vettel because finally I had the brakes cool enough to attack and I could ramp up the electric power, and I was going to really go for it."
His engine failure came after a poor start, a recovery and then a team decision to give his power unit a boost in the final laps.
"We gave it a little push at the end to try to catch Sebastian and this is when it decided to call it a day," said team boss Toto Wolff.
"The engine was on its sixth race so it was very high on miles and we didn't get any warnings."
