Spokesman Andrew Willis says that after Friday's recount the "official tabulation" has found PC candidate Gila Martow was the winner by 85 votes.
The initial count done on election night had given the seat, which sits north of Toronto, to Liberal Sandra Racco by that very same margin.
Elections Ontario caused some confusion, however, by announcing two versions of the final count. An English-language news release put the spread at 85 votes, while the corresponding release in French said Martow had won by just 60.
Elections Ontario later confirmed that the former number was correct.
That means the election results now have Ontario's Liberals with 58 seats compared to 28 for the Tories. The change doesn't affect the status of the Liberal majority government.
Willis says the new outcome was the result of a "very comprehensive review" of the vote calculation.
Two seats in GTA
The turnaround leaves the Tories with two seats in the Greater Toronto Area, which the Liberals dominated on election night. The Tories had three ridings in the GTA going into the election, but lost Etobicoke-Lakeshore with the defeat of incumbent and former Toronto deputy mayor Doug Holyday by Peter Milczyn.
The Tories also held onto Whitby-Oshawa, well to the east of the city.
Martow and Racco, along with NDP candidate Cindy Hackelberg, fought for the Thornhill seat earlier this year in a byelection that eventually went to the Tories by a margin of some six per cent. That win marked Martow's debut as an MPP. The riding has been held by the PCs since 2007.