St. Petersburg mayoral candidate Ken Welch landed what arguably could be his most important endorsement to date.

City Council member Darden Rice, who finished third in the crowded Aug. 24 Primary Election, offered her nod Wednesday.

"We are at a crucial point in the trajectory and future prospects of St. Petersburg. We cannot take for granted the momentum we have going or the serious challenges and issues we must address moving forward. That's why I'm so proud to endorse Ken Welch to be the next Mayor of St. Petersburg," Rice said in a statement.

"I'm certain that there is no one better suited to be our next Mayor than Ken. His endorsements look like the community, his experience will work for the community, and together we can uplift St. Pete for generations to come."

Her endorsement makes what was already difficult math for Welch's opponent, City Council member Robert Blackmon, even more complicated.

Welch finished the Primary with a full 11 percentage points more of the vote than Blackmon, at 39% to 28%. Rice collected just shy of 17% of the vote. More than 6,000 votes separated Welch and Blackmon, while Rice claimed more than 9,000, each from a supporter who may be encouraged to now cast a vote for Welch with their preferred candidate eliminated from the mix.

Those numbers hold in polling, too. A poll taken just days before last month's Primary showed Welch leading Blackmon in a hypothetical General Election with 53% support to Blackmon's 29%, a 24-point deficit.

That means Blackmon needs all the support he can get as General Election campaigning heats up. He can expect to collect at least some of the votes from Pete Boland, who finished fifth in the Primary. Boland and Blackmon were the only registered Republicans in the race. It's also possible he could pick up votes from former City Council member Wengay Newton, a Democrat who has a history of cross-party appeal. But the two combined account for fewer than 8,000 votes, fewer than Rice alone.

Votes for other candidates were negligible, just over 1,000 between University of South Florida St. Pete student Michael Ingram, small business owner Marcile Powers, community activist Tory Nelson and a write-in candidate.

While the race is nonpartisan — candidates' political affiliations don't appear on the ballot — it's no secret where they align. That puts Blackmon at a statistical disadvantage.

Among the city's nearly 190,000 registered voters, more than 88,000 are Democrats while fewer than 50,000 are Republicans, according to the Pinellas County Supervisor of Elections.

Rice's endorsement may come as a surprise to some. Ahead of the August election, Rice sent several critical mailers to voters targeting Welch. They attempted to tie the former Pinellas County Commissioner to former President Donald Trump, based on endorsements from Republicans, including Sheriff Bob Gualtieri, and campaign contributions from conservative individuals and groups.

But many voters saw the mailers as disingenuous — Rice also accepted donations from conservatives, formerly endorsed Blackmon over a Democrat for City Council, and Welch served as a delegate for now-President Joe Biden.

Still, the two appear to have put negative campaigning in the past.

"I've worked with Councilmember Darden Rice for over a decade on housing, transportation, economic and community development initiatives. With the Primary Election behind us, it's important that we focus on reconciliation, and work together to pursue our common goals of equitable and inclusive progress for St. Petersburg. I appreciate Councilmember Rice's endorsement and look forward to our future collaboration," Welch said.