Nico Rosberg expects Daniel Ricciardo to be a big threat in Sunday's Singapore Grand Prix after the Red Bull driver joined the German on the front row.
Rosberg - who has won both races since the mid-season break - continued his fine form with the fastest time in Saturday's qualifying at one minute 42.584 seconds.
But it was not his Mercedes team-mate Lewis Hamilton alongside him on the front row after Ricciardo produced a superb lap in Q3 to split the Silver Arrows.
Ricciardo's pace in the Red Bull is something of a concern for Rosberg, but he is confident he has enough to keep the Australian at bay on Sunday.
"That was one of my top three laps ever, and I'm so happy that it came on my 200th grand prix weekend," said Rosberg.
"It wasn't clear in qualifying how we would stack up against Red Bull so I really had to give it everything and pull it out of the bag, which is cool.
"Am I worried [about Ricciardo]? No, but I will be keeping an eye on him for sure. He will be a threat for sure, especially with that supersoft tyre."
Meanwhile, Hamilton rued another disappointing session as he finished seven tenths off his team-mate in third.
"It hasn't been my weekend so far," he said. "Nico did a great job and showed the real potential of the car."