Ernesto Viso and Enrique Bernoldi not only shrugged off their rookie credentials, but also provided added confidence to the Champ Car converts by leading Sunday's IndyCar event in St Petersburg.

The South American pair only joined the series at the last minute, but gave HVM Racing and Conquest Racing plenty of front-running exposure in an event eventually won by another former Champ Car team, as Newman/Haas/Lanigan took Graham Rahal to an IndyCar debut victory.

In their only second start in the series, Viso and Bernoldi eventually came home fourth and fifth in the Honda Grand Prix, the Venezuelan having climbed though the field from 15th position, and leading eleven laps along the way.

After the skies opened while the field was sitting on the pre-grid, the first ten laps of the race were run under caution as track cleaners attempted to reduce the large puddles forming on the course. Once released from behind the pace car, however, Viso drove a clean, consistent race, moving up five spots in only eight laps under green.

On lap 34, the HVM team decided to take a gamble with tyres, as the racing line was getting drier every time around. Viso pitted for slicks and fuel under caution, and the tactic proved right as the majority of the field made their stops under green. Viso duly moved up to third place, before passing both IRL veteran Vitor Meira and fellow newcomer Bernoldi and pulling away in the lead on lap 48.

Still distancing himself from the pack on lap 59, the Venezuelan's progress was halted by another caution and, although he received a beautiful stop from the HVM team, Viso found himself passed by IRL favourites Helio Castroneves and Tony Kanaan on consecutive restarts. Relegated to fifth position, he moved back into fourth when Ryan Hunter-Reay ran out of fuel with one lap remaining and remained there to the chequered flag.

"We had a great race strategy and a great car, and it almost paid out for us in the end," Viso commented, "I really like racing in the rain, but we took a gamble when we put the slick tyres on. Fortunately, it paid off for us. Had it not been for the last two yellows, we would have been on the podium for sure."

Bernoldi gained two places at the start, and continued to make steady progress up the order before joining Viso in the pits on lap 34, also fitting slicks. By lap 43, as the4 rest of the field made their stops, Bernoldi was into fourth place, but wasted little time before hitting the front to lead the first laps of his IndyCar career.

Although the Brazilian dropped back as the field pitted under yellow for Ryan Briscoe's meeting with the wall, he gained one place by passing Dan Wheldon for sixth on lap 68 and then gained another place in the dash to the flag after a final caution period caused by Conquest team-mate Franck Perera's collision was Meira.

"I've been racing in the wet and the dry and changing situations my whole life, so I was used to it," Bernoldi said afterwards, "I knew, if I could stay on the track, I could have a good race and fight for a win. I think, after last week at the oval, where I was so bad, it's a big week for the whole team to be leading the race and to finish fifth.

"I've been out of open-wheel racing for more than two years, so it takes a while for me to get back, but I think this was good practice."