The Silver Arrows had to settle for being the second fastest team in Friday practice for the Singapore Grand Prix.
'We had a clean day'
Lewis Hamilton and Valtteri Bottas ended the day third and fourth on the timesheets, as the two Red Bull cars set the pace on Pirelli's UltraSoft tyre around the Marina Bay Street Circuit.
"We had a clean day and got through our sessions without problems," said Lewis. "It was pretty hot out there, the conditions are pretty awesome to cope with, but the grip on the track is fairly good.
"We were obviously close with the field today and we have still got some improvements to make with the car. Red Bull seem like they're very strong and they're thereabouts with Ferrari, so we've got some work to do. But nothing is out of reach."
'This was a difficult day for us'
Valtteri was the first to swap to the UltraSoft in the evening session and went second fastest behind Lewis, only to be shuffled down to P4 as the Red Bulls improved.
"This was a difficult day for us, I think we are missing some pace," said Valtteri. "We were making big setup changes between the first and the second session, but still didn't quite find the right setting.
"There is plenty of work to do from what we learned today. I was struggling with the overall grip and the balance of the car.
"The car felt quite nervous, so it's not so easy to trust the car when you push. That's the main thing we need to work on so that I can build up my level of confidence."
'Lewis is showing some encouraging pace on the Soft tyre'
Silver Arrows Technical Director James Allison reflected on a mixed day for the team, with a rallying call to push on in search of more performance overnight.
"In terms of the programme, it was a clean and straightforward day, but performance-wise a bit more of a mixed bag," said James.
"Lewis is showing some encouraging pace on the Soft tyre, but we've got a bit more to do on the Qualifying tyre. Valtteri on the other hand had a tough day and we've got some work to do with him to get him up to Lewis' pace.
"The whole team needs to raise its game a bit overnight to be able to compete on even terms with the Red Bulls."