Lewis Hamilton has praised Mercedes for the effort in delivering its wide-ranging upgrade package at the Monaco Grand Prix.
But the seven-time F1 World Champion has conceded there is an area of performance the W14's updated specification is clearly lacking.
The Silver Arrows' changes see new front suspension, new floor and new bodywork added as the radical 'zeropod' aerodynamic concept has been sidelined.
Hamilton went third fastest in first practice before slipping to sixth in the second session and explained: "I have generally had an amazing day, I really enjoyed driving.
"I wanted to say a big thank you to everyone back in the factory because to build and design and develop a car is not an easy thing and everyone has put so much time and hours of hard work to have us here.
"I am glad we were able to keep it on track for them and I think we got a lot of data.
"It is not the place to test an upgrade but the car was generally feeling good. It was a shame we were not as close as we had hoped but definitely felt the improvements and I am grateful for them.
"We have just got to keep chipping away to see if we can squeeze any more juice out of the car."
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Clear where the lack of performance is
The changes were initially targeted at last weekend's Emilia Romagna Grand Prix but have been introduced at Monaco following the cancellation of the Imola event.
The circuit poses challenges in collecting vital data due to its unique layout, but when asked if there was a clear area of improvement for the W14, Hamilton replied: "There is and it is very clear where the lack of performance is for me.
"We will talk about it in the debrief, put our heads together and try and figure out how we can [improve] within what we have, but hopefully this is a platform we can build upon moving forwards."