The two have been battling hard for nearly a year, and it appears they will have to wait a bit longer to find out who has won the race.
Adding an added dose of uncertainty: Voters from two precincts have so far been unable to cast ballots — the precincts were closed due to damage from Tropical Storm Iselle, which hit the Hawaiian Islands on Friday.
Those two precincts, which have 8,000 registered voters between them, will have to vote absentee. State law says the vote must be held within 21 days.
Schatz touted his lead but stopped short of claiming victory.
"This is not how we drew this thing up, but it's a pretty good night for us," he told supporters in a speech. "We'll wait for the final results."
Hanabusa made it clear in a speech to supporters late Saturday night that she wasn't ready to concede.
"It is far from over," she said. "The night is still young, the election is still going."
Schatz added in a follow-up interview with KITV that he'd "work really hard" to win votes in the remaining two precincts.
"We're not quite celebrating because it's not quite over, but we're really pleased with our lead," he said.
Both candidates mentioned they would head to the Big Island soon, where the two outstanding precincts are.
The candidates face a tricky situation trying to woo voters in Puna, a more rural area that was hard-hit by the storm. Power is still out, and roads are still not passable in parts of the area, and both Schatz and Hanabusa would have to make sure not to alienate voters by being to aggressive with campaign tactics in an area still recovering from the hurricane.
And even after those precincts vote, one candidate or the other could push for a recount.
Schatz was appointed to replace Sen. Daniel Inouye (D-Hawaii) after his death in late 2012, despite Inouye's deathbed request that Hanabusa replace him. Hawaii Gov. Neil Abercrombie (D), who appointed Schatz, lost his primary on Saturday by a 2-to-1 margin.
The incumbent has outraised and outspent Hanabusa by a wide margin. While EMILY’s List has spent $500,000 on the congresswoman’s behalf, Schatz received support from the League of Conservation Voters and has had a 3-to-1 edge in TV ads in the closing weeks.
Schatz also trumpeted an endorsement from favorite son President Obama, helping to boost his name identification following his appointment.
— This post was updated at 5:15 a.m.