KANSAS CITY, Kan. (AP) — Timbers manager Giovanni Savarese wouldn't divulge what was said in the Portland locker room at halftime Thursday night, saying only that "a few words" might have come across rather sharply.

Whatever they were sure had an impact.

After getting dominated by Sporting Kansas City for the first 45 minutes and falling into a 1-0 hole, the Timbers rallied in the second half in the second leg of the Western Conference final. Diego Valeri scored a pair of goals, one of them in stoppage time, and Sebastian Blanco had the other as the Timbers squeaked out a 3-2 victory to advance to the MLS Cup for the second time in four years.

The Timbers will visit Atlanta United on Dec. 8 to play for the league title. Atlanta beat the New York Red Bulls 3-1 on aggregate to win the Eastern Conference final series.

"I'm very proud of the performance of the guys," Savarese said. "It was a very difficult first half and they were very good and we were lucky to be down 1-0. Then we came out with the fire we needed in the second half."

Sebastian Blanco got the rally started with his tying goal, and Valeri added the first of his two moments later. His second wasn't even needed because the teams had played to a scoreless draw Sunday in Portland, and that meant the Timbers had the road-goal tiebreaker in the event of a 2-2 tie.

Valeri's stoppage goal merely allowed the Timbers to celebrate a few minutes early.

"We played a great second half," he said. "The end of the first half we started to get on the ball a little better. We defended in the second half against a good team and we were efficient."

Ultimately, Portland solved what had been a near-impossible riddle.

Sporting KC had been 15-2-4 in home playoff games, their only losses coming in 1997 and 2011. Sporting KC also had been 12-2-5 at Children's Mercy Park this season, losing just three times in 48 matches across all competitions in one of the toughest venues in all of Major League Soccer.

The Timbers made it four defeats on Thursday night.

"Situations like this, they're going to stick with you for a long time," Sporting KC manager Peter Vermes said. "It's motivating factor in my opinion. I remember years ago playing against Houston at home, we won 1-0 but we didn't score enough and we lost. Today feels a little like that game. So yeah, it's going to be hopefully a motivating factor going into next year."

Sporting KC actually controlled the game when Daniel Salloi found the back of the net in the opening minutes, much to the delight of a packed crowd at Children's Mercy Park. Among them a handful of Kansas City Chiefs, including Patrick Mahomes, Kareem Hunt and Travis Kelce.

But the Timbers turned up the pressure in the second half, knowing any score-draw would send them through, and Blanco provided it when he unleashed a driving shot from 35 yards away. It somehow found a sliver between the hand of goalkeeper Tim Melia and the crossbar to knot the game 1-all.

"Blanco has scored some good goals," Savarese said, "but that one was incredible."

The strike in the 52nd minute was followed by Valeri's header off a rebound moments later, a goal that not only silenced the crowd but led to a rather bizarre scene.

Fans in one corner of the stadium began throwing bottles and other trash at Portland players, and referee Mark Geiger immediately brought both teams to the sideline. Vermes then stalked halfway across the field, waving his arms and admonishing his own club's fans.

"First time that we've ever experienced that here and I hope it's the last time," he said. "I never want to see that again. I don't think that has any place in the game."

Sporting KC was left needing two goals to win the game and advance, and nearly got in the 72nd minute. Johnny Russell's free kick from about 15 yards glanced off Felipe Gutierrez's head and sailed over the net as Portland goalkeeper Jeff Attinella exhaled in relief.

Gutierrez put another shot on goal moments later that Attinella kicked away.

"We had some chances to get there," Vermes said. "We definitely had some chances."

Fernandes finally got one of the goals Sporting KC needed, and the home crowd roared when it was announced that there would be nine minutes of stoppage time. But the Timbers managed to tamp down each attack by Sporting KC, allowing Savarese's team to begin planning for Atlanta.

"This is a group that works hard. That believed all along that we could be great," Savarese said, smiling. "I'm extremely proud of these guys right now."

More From 1460 ESPN