Los Angeles (AFP) - Cristian Arango struck a dramatic stoppage time winner as Los Angeles FC beat LA Galaxy 3-2 in a thrilling Major League Soccer Western Conference semi-final on Thursday.
France-born Gabon international Denis Bouanga had twice put Los Angeles FC, the playoff top seeds, ahead only to see the Galaxy fight back and level on both occasions.
But in the third minute of time added on, Galaxy keeper Jonathan Bond couldn't hold on to a volley from Bouanga and Colombian Arango pounced to fire home.
The striker, known as "Chicho" climbed into the stand at the Banc of California Stadium to celebrate with the raucous home crowd.
LAFC were without former Real Madrid and Tottenham Hotspur winger Gareth Bale, who was ruled out with a left leg injury while veteran Italian defender Giorgio Chiellini started on the bench.
Bouanga, signed in August from Saint Etienne, fired the home side ahead in the 23rd minute after good work from Mexican Carlos Vela.
But a minute before the interval, French winger Samuel Grandsir pulled the Galaxy level with a fierce drive after a poor headed clearance from Eddie Segura.
Bouanga restored LAFC's lead in the 80th minute, arriving at the back post to turn in a low cross from Ryan Hollingshead.
Galaxy coach Greg Vanney through on substitute Dejan Joveljic and within two minutes the move had paid off with the Serbian blasting in a superb shot from the edge of the box.
But then came the late drama as LAFC, winners of the 'Supporters Shield' for the best regular season record, booked a Western Conference final place against the winner of Sunday's all-Texan semi between Austin and Dallas.
Los Angeles will host the MLS Cup final should they reach the title game and head coach Steve Cherundolo said that despite the emotional nature of the derby win there was no risk of premature celebrations.
"This team is very focused and we will be ready for the next game and hoping for a final here," said the former US international defender.
"The game was an advertisement for MLS, that is MLS at its best, although for coaches maybe not so great," he added.
"Lots of goals, excitement and passion with two teams going at each other and it took our best to beat them," said Cherundolo.
The Philadelphia Union moved into the Eastern Conference final with a 1-0 home win over FC Cincinnati.
A 59th minute strike from Leon Flach earned the victory for a Union team which finished top of the Eastern Conference in the regular season.
The Union will face the winner of the game between Montreal and New York City FC, who play on Sunday.
Unbeaten at home this season, Philadelphia had a great chance to take the lead early but Hungarian midfielder Daniel Gazdag's headed effort from a central position was off target.
But it was the visitors who had the better of the opening half with Union keeper Andre Blake doing well to keep out an effort from Brandon Vazquez before Obinna Nwobodo flashed a shot just wide.
Blake was in action again after the break, diving at full stretch to keep out a Junior Moreno curler.
It was against the run of play then when the Union grabbed the lead with Danish midfielder Mikael Uhre finding Flach inside the box and the midfielder's first time left-foot shot flew into the top corner.
Cincinnati piled on the pressure in search of an equaliser but could not find a way past Blake who kept out a fine attempt from Argentine midfielder Luciano Acosta and again denied the dangerous Vazquez.
