Having first run at a filming day in Bahrain earlier this week, Russell had exclusive use of the car for the opening day of pre-season testing on Wednesday in Bahrain.
Despite ending the day a low-key 12th on the timesheets, 2.765 seconds adrift of the pacesetting Red Bull of Max Verstappen, Russell said the initial feedback from the car delivered some positive impressions.
Most encouraging of all was the fact that the new W15 has appeared to have got rid of the 'spiteful' rear end nervousness that hurt both him and Lewis Hamilton throughout last season.
Speaking at the end of the day, Russell said: “Overall, the W15 does feel nicer to drive than last year's car. We know that it's not about the feeling, but the speed. Nevertheless, today was about learning and not about chasing performance.
"We're focused on ourselves at this test, and it will only be next week where we see where we stack up against the others.”
Source: Autosport