Lewis Hamilton was beaten to pole position for Formula One's 1,000th race by ValtteriBottas.
In a nail-biting session, Bottas saw off the five-time world champion by just 0.023 seconds at the Shanghai International Circuit.
The form guide indicated that Ferrari might be the team to beat here, but after they were off the pace at the last round, Mercedes have returned to their all-conquering best.
Sebastian Vettel was a third of a second down on the Silver Arrows, with team-mate Charles Leclerc fourth. Red Bull's Max Verstappen finished fifth.
"It has been a good weekend so far," said Bottas. "I struggled to get the perfect lap in, but it was good enough."
Hamilton said: "I didn't give up and kept pushing right to the end. Valtteri has been stellar all weekend. I have struggled. There is time left on the table, but I will try and get it back tomorrow."
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Lewis Hamilton will be partnered by Valtteri Bottas next season after Mercedes confirmed the Finn has signed a new one-year extension.
Less than 24 hours after the Silver Arrows announced Hamilton will extend his stay with the team until 2020, it was revealed that Bottas will also be retained for at least more one year.
The 28-year-old Finnish driver, who was signed as a replacement for Nico Rosberg, has quietly impressed in his second full season at Mercedes, occasionally out-performing team-mate Hamilton.
Mercedes considered a move for Red Bull driver Daniel Ricciardo, out of contract at the end of the season, but remained faithful to Bottas. They also have an option to keep the Finn on for 2020.
Bottas is fifth in the drivers' championship, 59 points behind Hamilton,
Valtteri Bottas qualified on pole position for Sunday's Austrian Grand Prix with his Mercedes team-mate Lewis Hamilton down in eighth after a five-place grid penalty.
Hamilton was only quick enough to set the third fastest time in Q3 as his main title rival Sebastian Vettel took second for Ferrari to start alongside Bottas on the front row of the grid.
Vettel holds a 14-point lead heading into the race and will be hopeful of extending the gap to second-placed Hamilton, who drops down the field after an unscheduled gearbox change.
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