Sam Hauser has been an underrated contributor throughout the NBA Finals

DALLAS — Sam Hauser’s box score numbers won’t jump out at you. But the 26-year-old sharpshooter — who has famously never shot below 40% from three in a single basketball season — has been critical en route to the Celtics taking a 3-0 NBA Finals lead.

His impact was the loudest in Game 3, when he helped the Celtics weather an early Mavericks’ storm by hitting 3 first-half triples — and finishing the night with 9 points (3-4 FG) and 3 rebounds. The Celtics fell behind by 13 points in their first quarter at the American Airlines Center, but Hauser’s poise to sink two threes in the opening period helped them crawl back into the game and ultimately regain control to take a commanding series lead.

Hauser hasn’t had an eye-popping offensive playoff run — nine points was the most he’s scored since the first round of the postseason against Miami, when he exploded for 17 points in the series-clinching Game 5. He shot just 7% from three (hitting 1 of 14 attempts) in the Eastern Conference Finals, dealing with uncharacteristic shooting woes that compelled him to rewatch his YouTube highlights in order to regain some confidence.

“Just to know I’m still the same guy — it’s just shots aren’t going in sometimes.”

But, even through those struggles, he continued to play double-digit minutes and served as one of the most reliable players off the bench, spacing the floor and helping open up lanes for teammates like Jaylen Brown, Jayson Tatum and Jrue Holiday to capitalize on.

“If they’re hugged on me in the corner, it creates a driving lane for someone else and creates an advantage that way,” Hauser said.

In the Finals, he’s been particularly effective, not just offensively but also doing all the little things, whether that’s getting stops on Luka Doncic or grabbing contested rebounds….