Butch James' converted try with nine minutes to go put the Lions ahead by one, but the substitute was caught offside during a sustained Hurricanes drive eight minutes later to allow Barrett to steal the victory.
The lead changed hands nine times over the course of the match, as six tries were shared evenly and the game reverted to uncontested scrums after the Lions lost both of their starting props to injuries shortly before halftime.
But while Barrett was unable to convert any of the Canes' tries, his boot still had the final say as he slotted five penalties to the Lions' three.
"It was too tight for my liking but both sides had a similar attitude and never gave up," Hurricanes captain Conrad Smith said.
"When we put on two tries (for 27-18) I thought we had it, but they scored and the lead changed another two times, so it was just lucky the final whistle came when we were in front."
The game began at a furious pace which barely relented, and although Jaco Taute scored in the corner in the ninth minute, Lions flyhalf Elton Jantjies failed to convert.
With Barrett successful with penalties either side of that try the Hurricanes had a slender lead, but it came and went as he traded further penalties with Taute.
Fullback Andre Taylor's excellent finish in the corner under pressure from two Lions defenders gave the Hurricanes a 14-8 lead at the break, moments after the Lions lost their second front-rower to leave the scrums uncontested.
"I thought we were doing quite well up front and we really wanted to keep that going in the scrums, which is one of our points of attack, so it was a bit of a loss for us," Lions prop Patric Cilliers admitted.
Nevertheless, the home side fought back, with Jantjies making a crucial line break during a run from inside his own half, which ultimately saw lock Franco Van der Merwe crash over the line from a pick and go.
Jantjies' conversion put the Lions ahead by a point, but the Hurricanes came storming back with tries from Dane Coles and Cory Jane to take a 27-18 lead with 20 minutes to go.
Coles showed great pace for a hooker to pounce on Smith's clever kick ahead to him from a dropped Lions pass, while Jane was gifted a simple finish two minutes later thanks to Barrett's grubber in behind the Lions defence.
Jantjies put the Lions back in range with a penalty eight minutes later before James' seventh Super Rugby try gave them the lead.
But it was not to be for the home side as Barrett's simple penalty gave the Hurricanes four important points.
"I think we let ourselves down tonight; they were hungrier than us and we made a lot of silly mistakes, and that's what you get," Lions captain Josh Strauss said. "I think when we kept the ball we did well, but we gave a lot of ball away and they made us pay."
Hurricanes 30 (Andre Taylor, Dane Coles, Cory Jane tries; Beauden Barrett 5 penalties), Lions 28 (Jaco Taute, Franco Van der Merwe, Butch James tries; Elton Jantjies 2 conversions, 2 penalties, Taute penalty). HT: 14-8
