The Portland Timbers drew 2-2 with FC Dallas, but still came out on top as 5-3 aggregate winners in Major League Soccer's Western Conference finals on an unseasonably cold night in Dallas.
Both teams had chances in a back-and-forth opening 45 minutes, but neither could break through.
Portland's Fanendo Adi broke the ice for the visitors early in the second half, when he settled a cross in the center of the Dallas penalty area, pivoted and powered a shot past goalkeeper Jesse Gonzalez.
Dallas answered in the 68th minute, when Mauro Diaz found Ryan Hollingshead with a beautiful chip and the midfielder volleyed home past Adam Kwarasey.
Minutes later, Blas Perez's header from a set piece gave Dallas a 2-1 lead in the game and cut its aggregate deficit to 4-3.
With Portland holding on for the win, Lucas Melano scored a magnificent goal to secure the win for his team as he literally walked the ball into the net past a helpless Gonzalez.
Despite holding a 3-1 advantage from the opening leg and playing without injured defender Liam Ridgewell, Caleb Porter's team came out on the offensive to start the game, looking to pad its lead with an away goal.
Dallas' best chance in the first half came in the 32nd minute, when Kellyn Acosta's curled cross found David Texeira right in front of the Portland goal. However, Texeira's close-range header was saved by Kwarasey.
Portland threatened in the 43rd minute as Darlington Nagbe and Dairon Asprilla charged down the left flank on a counterattack. Asprilla played a perfect cross through Dallas' six-yard box, but Adi couldn't catch up to the ball.
Dallas almost scored five minutes into the second half from a set piece, but no FCD players could get on the back end of Diaz's well-played cross.
Portland will play the winner of the Eastern Conference finals between the New York Red Bulls and Columbus Crew SC in the club's first-ever MLS Cup appearance.