Cristian Arango fired home a dramatic 93rd-minute winner as LAFC won their Battle of the LA Conference Semifinal 3-2 over LA Galaxy in the MLS Cup on Thursday.

Arango's goal capped a wild final 15 minutes where three goals were scored in the clash at Banc of California Stadium, with Galaxy substitute Devan Joveljic having curled in an 85th-minute equalizer.

The win means Western Conference top seed LAFC progressed to the Conference Finals where they will host either Dallas or Austin.

LAFC had taken a 23rd-minute lead when Carlos Vela slipped in a pass for Denis Bouanga to clinically score, but Galaxy leveled before the break when Samuel Grandsir lashed home a bouncing shot.

Bouanga restored LAFC's advantage in the 80th minute when he tapped in Ryan Hollingshead's low ball across goal.

But Joveljic scored barely a minute after entering the game as a substitute, curling in from the edge of the box.

LAFC would find a winner in the third of six additional minutes in stoppage time, when Kellyn Acosta's corner found Bouanga whose volley was parried by Galaxy goalkeeper Jonathan Bond into Arango's path and he lashed in the rebound.

Eastern Conference top seed Philadelphia Union also advanced into the last four, winning 1-0 over Cincinnati at Subaru Park.

Leon Flach scored the winner in the 59th minute with a left-foot strike, marking his first goal since October last year.

Union goalkeeper Andre Blake made several key saves, including an 83rd-minute block to deny Brandon Vasquez's chance to ensure Philadelphia hosted the Eastern Conference Final for the second straight year. They will welcome either 2021 MLS Cup winners New York City or Montreal.