Daniel Ricciardo has struggled in the second practice session for Sunday's Chinese Formula One Grand Prix in Shanghai.
The Australian, fourth in Friday's first session for Red Bull, couldn't string a clean lap together later and finished the day only ninth, ahead of McLaren's Fernando Alonso who rounded out the top 10.
World champion Lewis Hamilton edged out Kimi Raikkonen on the timesheets, as Ferrari ended practice hot on pacesetter Mercedes' heels.
The Briton lapped the 5.4 km Shanghai International Circuit in one minute, 33.482 seconds in the afternoon session, beating Raikkonen by 0.007 seconds.
Hamilton's Mercedes teammate Valtteri Bottas was third, 0.033 seconds off the pace, with Ferrari's championship leader Sebastian Vettel fourth, 0.108 seconds short of his rival's best.
The top three finished in the same order as they had ended the opening 90 minutes of practice.
"We got through all the laps that we needed and got some good feedback about the car," said Hamilton.
"The balance of the car is good but we have some fine-tuning to do on it tonight. Ferrari were quick and Red Bull looked really fast on the long run."
The best Vettel had managed in the morning had been sixth, 0.862 seconds off Hamilton's pace.
Hamilton is determined to claw back at least some of his 17-point deficit from Vettel in the overall standings. The German powered to victory in the opening two races in Australia and Bahrain.
The Briton, like Vettel a four-time world champion, has won in Shanghai on an unprecedented five occasions.
Red Bull's Max Verstappen was fifth quickest in both sessions, closing to 0.341 seconds off Hamilton's pace. Renault's Nico Hulkenberg was sixth.
"We spent a bit of time during the first session today working on the set-up of the car in order to understand it better," explained Verstappen.
"By the end of the day, the pace was looking good and I think we can be happy with the car's performance."
Kevin Magnussen was seventh for US-owned Haas ahead of the other Renault of Spaniard Carlos Sainz.
The session was hit by rain in the closing stages.
Stoffel Vandoorne stopped his McLaren out on track with a loose wheel, while a wing mirror fell off Russian rookie Sergey Sirotkin's Williams.
Several other drivers spun or went off the track, tested by cool and blustery conditions.