Heavy rain brought an end to the final day of the IndyCar Series' four-day open test at Sebring International Raceway, but not before Ryan Briscoe had turned in a quick lap to maintain top spot for Team Penske.
Without the final 45 minutes of planned running to respond, the Australian's rivals were unable to match his 52.4202secs effort, which was three-tenths faster than he had managed on the first day that his half of the field had tested on Wednesday.
Briscoe edged Penske team-mate Helio Castroneves by three-hundredths of a second as, together, the two red-and-white cars dominated proceedings, lapping more than a half second quicker than anyone else - including the Target Chip Ganassi pairing of Dan Wheldon and Scott Dixon, who occupied third and fourth spots.
"The track was really quick this afternoon," Briscoe reported, "Helio turned a fast lap mid-session, so we had something to shoot for. We went out on new tyres, but we weren't quite happy with the car, so I had to come in. We made a change, which proved to be very effective.
"It is amazing what a small adjustment can do to lap times around this circuit. The Team Penske car was performing very well at the end of the session and I think we made a lot of progress today."
Wheldon managed to fend off Dixon's advances by a scant hundredth of a second, while fellow Briton Darren Manning slotted into fifth spot for AJ Foyt Enterprises. Manning was three-hundredths off Wheldon's pace, and comfortably ahead of Panther's Vitor Meira in sixth.
Buddy Rice and Townsend Bell brought up the rear of the eight-car field for Dreyer & Reinbold Racing.
Testing times - Sebring (6 March):
Ryan Briscoe Penske
52.4202secs
Helio Castroneves Penske
52.4531secs
Dan Wheldon Ganassi
53.0131secs
Scott Dixon Ganassi
53.0286secs
Darren Manning Foyt
53.0433secs
Vitor Meira Panther
53.2467secs
Buddy Rice Dreyer & Reinbold
53.3859secs
Townsend Bell Dreyer & Reinbold
54.0505secs
