Bale, who came in as a late substitute after sitting out the playoffs with a wrist injury, headed home a cross from Diego Palacios over Union's Jack Elliott to level at 3-3.

Game MVP McCarthy, who came on after Maxime Crepeau was carted off the field following a hard collision with Cory Burke, rose to the occasion, making terrific saves to secure the 3-0 victory in penalties in Los Angeles on Saturday.

Urged on by their rowdy fans, the home side were the aggressors early and broke through in the 28th minute when a free kick by Kellyn Acosta deflected off the head of the Union's Jack McGlynn and past keeper Andre Blake.

In the second half, Philadelphia's Jose Martinez misfired on a shot from distance but the ball found Daniel Gazdag, who buried it into the back of the net to level the contest at 1-1.

LAFC went ahead again in the 83rd minute when Jesus Murillo raced to the goal and rose up to head home a perfectly placed corner kick from Carlos Vela that appeared to be the game winner.

But the lead would prove short-lived, with Philly leveling again two minutes later on a set piece taken by Kai Wagner that Jack Elliott headed past Maxime Crepeau for 2-2.

Elliott struck again in the 124th minute to give the visitors their first lead of the game before Bale's heroics four minutes later sent the rollercoaster match to penalties.

Ilie Sanchez scored the decisive penalty to deliver the championship for the club, which joined the North American league in 2018.

Australian Associated Press