Nico Rosberg admitted he was "on a knife edge" as he pushed to secure a front-row start for Sunday's Indian Grand Prix.
The Mercedes driver will start from second place behind Red Bull's Sebastian Vettel, who claimed a dominant pole position by over seven tenths of a second.
Rosberg admitted he had to extract every drop of performance from his car in order to even get that close.
"I am completely on a knife's edge, really pushing to the limit, trying to extract that tenth more out of the car," said Rosberg, who had last started from the front row in Singapore.
"Qualifying second was better than I hoped for because of Mark [Webber] being on another strategy. The race is going to be tough."
Like Vettel, Rosberg will start the race with the softer tyres, but he denied the strategy was a gamble.
"Of course it's always a consideration, but we decided that the soft tyre was the best way to go. It's not a gamble, it was the best thing to do."
Team-mate Lewis Hamilton qualified in third, the Briton admitting Mercedes is unlikely to be able to battle Vettel in the race.
"I've struggled with something different on the car this weekend which Nico had experienced in the past," he said.
"I'm happy with the result and laptime I could get. We will try to push these guys as much as possible but they are in another world and we will try to be the best of the rest."