Brawn GP pairing Jenson Button and Rubens Barrichello may not figure too highly in the estimation of Renault F1 managing director Flavio Briatore [see separate story - click here], but that did not stop them from once again leading the way in free practice for this weekend's Chinese Grand Prix.

The Brawn GP BGP 001 has been the class of the field in the early phase of 2009, and having thoroughly dominated the opening two grands prix of the season in Australia and Malaysia in the hands of Button, has now been ruled fully legal following the FIA Court of Appeal's diffuser verdict earlier this week.

With both drivers figuring inside the top three throughout the day in Shanghai - respectively second and first (Button) and third on both occasions (Barrichello), as they worked on fine-tuning the balance and set-up of the Brackley-based concern's Mercedes-powered challenger, in addition to performing tyre comparisons of the two compounds Bridgestone has brought for the race - that hegemony shows few signs of easing up anytime soon.

"The balance of the car really improved over the last couple of runs today after we had been struggling a little to find the right set-up early on," reported Button. "We completed a great deal of work with the two very different tyre compounds to establish what condition they would be in after longer runs.

"There seemed to be a lot of traffic on-track today, so my main concern was finding some clear air. It was a useful first day of running, but we still have some work to do tomorrow to be happy with the balance for qualifying."

"Another positive Friday," agreed team-mate Barrichello, "and we achieved some good work today which will set us up well going into the weekend. Our main focus was on the tyres and evaluating the best way of looking after the softer option tyre, and it was very useful to find out what the tyres are capable of.

"We tried various things but I did struggle for grip with my last set of tyres this afternoon. There are a lot of marbles on the track at the moment, but it should clean up going into the weekend."

On a day when the former Honda F1 outfit announced a new, three-year sponsorship deal with successful Swiss-based foreign exchange trading company M I G Investments, team principal Ross Brawn concluded that all was running to plan - even if there could be no let-up if the squad is to uphold its perfect start to the new campaign and pull off the hat-trick on Sunday.

"We have had a productive day," summarised the Englishman, "which has enabled us to complete a thorough evaluation of the prime and option tyres ahead of the weekend. Our main focus was on the softer option tyre, and establishing the best way to work with this compound in qualifying and the race.

"Although we are not quite satisfied with the balance yet, the car worked well in the cooler temperatures that we are experiencing this weekend with the race taking place six months earlier than usual.

"We are also delighted to welcome M I G Investments to Formula 1 and to the Brawn GP team. Our team has had a great start to the 2009 Formula 1 season, and we are very pleased to have secured our third new partnership.

"In a difficult economic climate, it is a positive sign that the appeal of Formula 1 continues to attract new companies to invest in our sport. We look forward to working closely with M I G Investments, to help drive global awareness of their brand through the powerful communications platform of Formula 1."

"We are extremely proud to be joining ranks with Formula 1's newest sensation, the Brawn GP team," added Hisham Mansour, CEO of M I G Investments. "This collaboration marks an important synergy between two young, innovative and ambitious teams, both leaders in our respective fields.

"We share parallel formulas for success and believe strongly in the power of innovation, teamwork and dedication. Our partnership with Brawn GP is further testimony to our strong industry position and confidence. We look forward to a fruitful and rewarding relationship together."