Kyle Kaiser secured the 2017 Indy Lights title with seventh place in a wet season finale at Watkins Glen.
The Juncos Racing driver needed only to start the race to be sure of the title thanks to starting with a 31-point advantage over Santiago Urrutia.
Other than a spin at the exit of the Inner Loop, he drove a conservative race to finish seventh ahead of team-mate Nicolas Dapero and was crowned champion after a season in which he won three races.
Aaron Telitz mastered the tricky conditions to win the race after battling with polesitter Colton Herta during the early laps.
Telitz's greater confidence in the tricky conditions allowed him to get ahead and build a gap over Herta.
After clearing Herta, Urrutia started to reel Telitz in - the Uruguayan halving the gap from eight to four seconds by half distance.
A caution was called shortly after for Dalton Kellett, who lost control of his Andretti-run Dallara on the exit of the bus-stop section. This allowed Urrutia to close up to Telitz.
Although the race was due to restart after Kellett's wreckage was cleared, the red flag was waved on lap 18 as the deluge began to worsen under the safety car.
After the rain subsided, the race restarted with seven laps to go, setting up a showdown between Telitz and Urrutia.
Urrutia - who is expected to announce a move to IndyCar next season at Sonoma - battled his Belardi team-mate hard, but Telitz was able to weather the storm and eke out a gap to secure his second win of the season.
Herta came under attack from Carlin's Matheus Leist in the final laps, but the Andretti Steinbrenner driver held off the Brazilian to clinch the final podium position.
Nico Jamin and Zachary Claman DeMelo, both passed by Leist before the restart, finished fifth and sixth respectively.
Juan Piedrahita finished ninth behind the two Juncos drivers, jumping Ryan Norman early in the race after the Andretti driver spun at turn 9 in the early stages of the race.