(CNN) Republican Kelly Ayotte has conceded the race for her US Senate seat in New Hampshire to Democratic challenger Maggie Hassan, according to a statement from Ayotte's campaign, giving Democrats their second pick-up in the chamber this election cycle.

"I just spoke with Governor Hassan to congratulate her on her election to serve in the U.S. Senate," Ayotte said in the statement. "I wish Governor Hassan, her husband Tom, and their children Ben and Meg the very best."

Hassan's victory makes the count for senators that caucus with Democrats 48 seats, short of the majority they were aiming for before Election Day. Tammy Duckworth of Illinois was the only other Democratic pick-up of the night, which saw Republicans retain their control over their conference and Donald Trump win his bid for the presidency.

Democrats also won a competitive race in Nevada, where Catherine Cortez Masto held off Republican Rep. Joe Heck to retain the seat being vacated by retiring Senate Democratic leader Harry Reid.

Those were Democrats' only three victories in a night that saw Republicans win nearly every close race, retaining their House and Senate majorities and guaranteeing the party has full control of Congress when President-elect Donald Trump is sworn in on January 20, 2017.

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