Nine months after now-Rep. Bob Turner (R) won an upset victory in the heart of New York City, there could be another electoral surprise next Tuesday in Queens.

The outcome of the contentious primary won’t cost House Democrats a seat, but party leaders could be dealt an embarrassing loss.

Assemblywoman Grace Meng faces ambitious Assemblyman Rory Lancman and New York City Councilwoman Elizabeth Crowley in the Democratic primary in the deeply diverse, reconfigured 6th district. Meng is backed by Rep. Joe Crowley, the chairman of the Queens County Democratic Party and the cousin of Councilwoman Crowley. Also on the ballot is physician Robert Mittman, who will probably come in fourth place.

Congressman Crowley, who helped pick the party’s nominee in the September special election that brought Turner to Congress, will take a hit if Meng loses, insiders said.

“One should not underestimate Mr. Crowley’s strong desire to win this,” one New York Democratic operative said, noting that the Congressman was pushing hard to avoid a Meng loss. “I think he would not like that outcome to happen for reasons related to the perceived strengths of the county organization.”

Regardless of the outcome, in a borough with a large Asian population, Crowley supporting an Asian-American candidate is probably smart politics.

And Crowley allies said he remains a key power broker in New York politics no matter what happens.

“He’s certainly invested in it,” one Crowley ally in New York City said, but “it’s not the be-all and end-all for him.”

Tuesday “is going to be a referendum of how good a campaign did Grace Meng run,” the source added. “If you’ve got the most money and the largest ethnic base, you should win.”

Meng has both. Almost 40 percent of the voting-age population in the district is Asian, and she had $345,000 in cash on hand on June 6.

A top Democratic strategist in New York said that the crowded field, redistricting and the ethnic politics at play in the race “make this a little bit less of a litmus test” on Crowley’s power than conventional wisdom would portray. But, the strategist said, a Meng win would be a real boon for Crowley’s reputation.

Lancman, who appears locked in a contest for first with Meng, had some momentum last week as he received the endorsement of the New York Daily News and the Queens Chronicle.

“The home stretch! It’s going exceedingly well,” Lancman said in an interview Friday. “We’re peaking at the right time.”

But the New York Times endorsed Meng on Saturday, belying that Lancman is an insurgent candidate. Meng has the support of the establishment, from politicians such as retiring Rep. Gary Ackerman (D-N.Y.) to the backing of outside groups such as EMILY’s List.

EMILY’s List has dropped more than $100,000 on independent expenditures in favor of Meng.

It’s unclear just how much of an effect Ackerman’s endorsement will have because the majority of the district is not his current territory.

Turner represents just less than half of the new district’s residents, while Ackerman represents about 38 percent of them.

Meng’s campaign got off to a shaky start, and she admitted as much in an interview Friday.

“It was a very short runway and we suddenly and unexpectedly had to start a Congressional campaign, and it was not the easiest start,” she said.

Meng was bullish on the state of campaign, saying “the momentum is behind us.”

Meng has outraised Crowley and Lancman, according to the most recent Federal Election Commission filings. And she said every night her campaign has 20 to 30 people knocking on doors. Meng noted that her campaign has mailed more literature to voters than any other campaign.

In a nod to the district’s diversity, Meng said her campaign has literature in English, Spanish, Korean, Chinese, Russian, Greek and Bengali.

Lancman is Jewish and has worked to appeal to the considerable Jewish population in the 6th.

Meng said ethnicity would be a component in any election, but she noted that appealing to a single ethnic base of voters wouldn’t be enough win in the heavily Democratic district.

“We each have to go beyond our so-called voter base,” she said. “I can’t win just based on the Asians. He can’t win just based on the Jewish vote. Liz can’t win just based on the Irish votes.”

Turnout is also an issue to watch. Congressional primaries have traditionally been held in New York state in September. But this year, a judge ordered the Congressional primary to be held in June.

“Even the most tuned-in voters are not going to know what’s going on,” the top New York Democratic strategist said.

Meng will have the considerable force of the Queens Democratic Party’s get-out-the-vote effort behind her. Lancman, however, has the backing of the Working Families Party and some unions with GOTV experience.

All the factors at play leave unaffiliated New York Democrats unsure of what will transpire Tuesday night.

Crowley was bullish on Meng’s chances.

“Grace Meng is on the cusp of making history as the first Asian-American elected to the U.S. Congress from New York,” the Congressman said. “I’m proud to support Grace in the primary because she is the right fit for the district.”