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."