Larsen led home former national champ Dean Brindle (Hamilton) and Te Awamutu's Brian Edwards to win the 20-lapper.
Larsen said track conditions had significantly improved since early season events at Baypark.
"The track was really good tonight. I don't know if it was a few less cars running on it or they got more water into it, but the last two times we've been here the track has been awesome."
The sprint car main event was interrupted by two caution periods and each of the three segments saw a different driver leading the pursuit of Larsen.
Skinny Colson ran in a strong second early in the race but after the first re-start it was Edwards who shot from fourth to second. On the last re-start Brindle grabbed the second spot.
Earlier in the night the sprint car heat races were won by Larsen and Brindle.
Thames racer Matt Smith dominated the super saloon car racing, winning both heat races and cashed up the Rolling Thunder purse by winning the feature race by almost half-a-lap ahead of Mark Hutchens and Stratford visitor Craig Korff.
The Formula 2 Midgets from Auckland's Western Springs produced some entertaining racing on their second visit to Baypark this season.
Darryl Webster and Corbin Anderson posted heat race wins and, with a close battle happening behind him, Anderson won the feature race.
In Palmerston North on Saturday night Tauranga's Chris Cowling raced to his third straight feature race win in the Burger King Pro Dirt Super Saloon Car series and clinched the seven-round series.
Cowling defeated visiting US racer Bobby Pierce in the 30-lap feature race and has doubled up with back-to-back Pro Dirt Series titles. Baypark drivers Steve Cowling and Sam Waddell finished second and third overall in the series.