A powerful explosion first hit an army checkpoint late on December 27, followed by an hours-long gunbattle, provincial spokesman Omar Zawak said.
The attack also wounded four soldiers, he said.
Taliban spokesman Qari Yusouf Ahmadi claimed responsibility for the attack, saying the group also seized weapons and ammunition.
The insurgents have a strong presence in Helmand Province.
The Taliban has increased its attacks in recent days against Afghan Army bases and checkpoints across different provinces.
Last week, six Afghan soldiers were killed when a suicide bomber detonated a car laden with explosives outside an army compound in northern Balkh Province. Militants then stormed the compound.
The Taliban claimed responsibility for that attack.
On December 23, an American soldier was killed in combat in northern Kunduz Province.
The Taliban claimed it was behind a fatal roadside bombing that targeted American and Afghan forces in Kunduz.
Taliban militants continue to stage near-daily attacks targeting Afghan and U.S. forces, as well as government officials — even as the group holds peace talks with a U.S. envoy tasked with negotiating an end to the military conflict in Afghanistan.
Scores of Afghan civilians have also been killed in crossfire or by roadside bombs planted by militants.