“I can't guarantee that every young man out there is old enough to vote, but every young man out there knows that we've been in this community for eight months,” Rocha told POLITICO on the sidelines. “And they'll be talking to their friends who can go vote, and go home to their parents and talk about Bernie Sanders buying everybody food while we played soccer [and] watch[ed] over their children while they were here in this park.”

Nevada presents the first test of Sanders ability to turn out Latinos. If he does well among the key demographic — which could account for 20 percent of caucus-goers — it could provide a recipe for continued success among Latinos on Super Tuesday, in states such as California, Texas, and North Carolina.

The campaign says it’s spent millions on Latino outreach in Nevada. Of the 250 staffers in the state, more than 100 of them are people of color and 76 are Latinos. Sanders is targeting Latinos on digital platforms like YouTube, Hulu, and Pandora; with mailers, TV ads, phone calls, and texting; and via old-fashioned door-knocking and community events. The campaign has held 35 of those in Spanish.

Polling backs up Sanders advisers' confidence that the efforts — crafted with the knowledge of their 2016 missteps in mind — will pay off in the first nominating contest with a diverse voting population.

In a pair of polls released Tuesday, Sanders and Joe Biden placed first and second among Latinos. A Univision poll conducted Feb. 9-14 had Sanders ahead, with 33 percent support among Latinos compared to 22 percent for Biden. A Telemundo poll conducted Feb. 10 - 12 showed Biden at 34 percent among Latinos vs. 31 percent for Sanders — although the pollster believes Sanders is now ahead because of the bounce he got from winning New Hampshire.

“He’s put in the work,” Laura Martin, executive director of the Progressive Leadership Alliance of Nevada, said of Sanders. Martin said she was stunned by the number of people Sanders’ campaign was busing to early voting locations last weekend. Martin also credtied the Sanders campaign work in securing endorsements from national progressive Latino groups that have helped bolster his ground game in states like Nevada.

Sanders has been on Spanish-language TV for the past six weeks, spending more than $130,000 in the final month. Only billionaire Tom Steyer has invested more, dropping more than $200,000 during that span. Steyer also went up with ads earlier in December.

Biden, whose campaign is predicting a second-place finish in Nevada, is the only candidate who is not on Spanish-language TV in the final stretch. According to a campaign source with knowledge of Biden’s paid communication strategy, Biden’s Latino supporters in Nevada primarily speak English as their first language and are older than 40, while his percentage of Spanish-speaking supporters ranks in the mid-single digits.

“Latino voters are paying attention and Bernie got a bounce from New Hampshire,” said Brad Coker, who conducted the Telemundo/Mason-Dixon poll. “Biden’s going to need to win two-thirds of Latino voters to win Nevada, anyway. And he doesn’t have that.”

Biden’s campaign and surrogates deny they're ceding the Latino vote.

Rep. Filemon Vela (D-Texas) canvassed for Biden over the weekend in minority neighborhoods around Las Vegas. He said he's sensing "overwhelming support for Biden" among Latinos 40 and over, based on his conversations with voters.

Also, some pollsters question the depth of Sanders’ support among Latinos in Nevada and elsewhere.

Stephanie Valencia of the Latino-focused Equis Labs, said it remains to be seen whether it’s Sanders "the candidate" or the broader "movement" he’s leading that attracts Latinos. Her polling reflects Sanders' strength among the demographic, especially young Latinas.

“Do people who are Latino Bernie supporters feel so strongly about him that they're going to show up and caucus for him?” Valencia said. “Because it's one thing to show up and vote for somebody, it's another thing to go and caucus for somebody.”

But Sanders’ campaign is acutely aware that his polling strength among young Latinos won't necessarily translate in a caucus state like Nevada, given the time and effort required of voters. Young voters, regardless of race, are historically the least likely group to turn out.

That’s why his campaign said starting early was crucial. In 2016, his advisers didn’t realize Sanders' potential with Latinos until late, said Rocha. Everything was “moving so fast, we never had time to go build our relationships in that community,” he said.

“We wanted to start the campaign where we left off, so we started in the Latino neighborhoods,” Rocha said. The first of 11 field offices it opened in Nevada was in the largely Latino East Las Vegas. And the first TV ads Sanders purchased in the state were in Spanish. “We’re blowing people out organizing-wise,” Rocha said.

Ironically, part of the campaign's effectiveness among Latinos stems from the fact that it did not create a separate arm for courting Latinos, said Analilia Mejia, Sanders' national political director. Instead, outreach to Latinos was integrated into every part of the organization. No matter the topic of a press release, Mejia said, a Latino staffer has looked at it before it goes out.

One of Sanders’ first messages to Latinos in Nevada came in an August mailer that told the senator’s family immigration story. That was followed by issue-specific mailers, including one in November prominently featuring progressive star Rep. Alexandria Ocasio-Cortez (D-N.Y.). Ocasio-Cortez held a town hall for Sanders in December entirely in Spanish, a rarity that drew widespread notice in the Latino community. Notably, Ocasio-Cortez is not scheduled to campaign for Sanders in Nevada in the final days before the caucuses.

Sanders' final Spanish-language TV ad to Latinos this week was narrated, written and produced by Dreamers on his staff, according to the campaign.

Sanders' rivals are trying to loosen his perceived grip on Latinos. Pete Buttigieg, Elizabeth Warren, and Amy Klobuchar all joined Sanders and Steyer on Spanish-language airwaves in the past two weeks. Warren met with the Latino organizing group Mi Familia Vota and held an event with Culinary Union workers. She's also been joined by Julián Castro, a top Latino endorser, throughout the week.

Buttigieg campaign co-chair Nelda Martinez, a Texas mayor, is scheduled to campaign in Nevada this week. Buttigieg, Steyer and Klobuchar sat down with Telemundo in Nevad for a presidential townhall last week as Sanders tele-conferenced in.

Sanders' biggest vulnerability among Latinos and all Democrats — attacks on him by the state's powerful Culinary Union — was likely mitigated by the union's decision not to endorse another candidate.

“The fact that [Culinary Union] chose to stay neutral means they're essentially allowing Latinos to make their own decision on their own,” said Andres Ramirez, a Nevada political consultant. “Had Culinary endorsed Biden or Klobuchar, then I think it would have made a big difference.”

Marc Caputo contributed to this report.