Timing is always mentioned when talking about Raul Ruidiaz’s goals.

On Tuesday, it was the striker’s second-half stoppage-time goal that lifted the Sounders FC to a 1-0 Leagues Cup semifinal victory over Santos Laguna at Lumen Field. The result booked Seattle to the tournament final in Las Vegas on Sept. 22.

“It’s difficult to maintain that level of confidence, that level of quality in front of goal, in big moments and big games, but (Raul) does it each and every time,” Sounders midfielder Cristian Roldan said. “You’ve got to have that killer and Raul is that killer for us.”

Ruidiaz’s shot was on a rebound after Santos goalkeeper Gibran Lajud deflected the forward’s first attempt. Sounders newcomer Leo Chu had the perfect through ball to help Ruidiaz break free for the initial shot.

Tournament rules called for the match to be decided by penalty kicks instead of overtime if the sides were level at the end of regulation. Sounders coach Brian Schmetzer said substituting Leo Chu, a Brazilian who signed in August, in the 82nd minute for midfielder Kelyn Rowe was part of getting “fresh legs” on the field since most of the players saw minutes in the home victory over Minnesota United FC on Saturday.

“I was feeling very confident,” Leo Chu said, as translated from Portuguese. “I knew if I entered the match that I could help the team. So, I’m very happy about the pass, the fact that it ended in a goal.”

Schmetzer substituted forward Will Bruin on for Alex Roldan in the 89th minute to be the possible fifth player to take a penalty kick. Santos coach Guillermo Almada also made substitutions, his three began in the 81st minute.

“Then, as the goal was going in, we were so overjoyed, we didn’t know what to think,” Schmetzer said of Ruidiaz’s score. “It was just pandemonium, a little bit, we were so happy like the rest of the fans and the people at home watching TV, everybody. We were just celebrating.

“Tonight was a really hard game against a quality opponent, I can’t say that enough. (But) it was an entertaining game, even though it was 1-0. It was back-and-forth and I thought it was good.”

Seattle is the only remaining Major League Soccer team in the single-elimination tournament. Orlando City SC, Sporting Kansas City and New York City FC all lost in the quarterfinal round.

The Sounders will face the winner of the semifinal match between Club Leon and Pumas UNAM, which will be played Wednesday in Houston.

The opening half was a series of eye-popping misses for the Sounders that still entertained the crowd of 12,201, including some cheering for Santos. Fredy Montero, the club’s all-time leading scorer, had a bicycle-kick attempt in the 38th minute that floated over goal.

In the 43rd minute, Ruidiaz, who leads MLS with 14 goals, missed a perfect pass from Roldan by an eyelash. If the connection could have been made, Ruidiaz likely would have had the score in the box.

The sides were even in possession, with Santos edging Seattle 7-6 in attempts in the opening half. Santos defender Felix Torres’ right-footed shot from outside the box created the only save of the half, Sounders keeper Stefan Frei easily catching the ball in the 41st minute.

Sounders midfielder Nico Lodeiro (hamstring) and defender Nouhou (leg) were not selected due to minor injuries. Both are expected to be available for selection against Real Salt Lake on Saturday.

“I purposely kept those guys out because they had a little soreness,” Schmetzer said. “This club is (winning) in many different ways with many different lineups. … My message after the game was to enjoy this moment because we should enjoy this moment. We’re in a Final.”

Ruidiaz and defender Xavier Arreaga made their first appearances for the Sounders since August due to international duty. Ruidiaz was a substitute in Peru’s three World Cup qualifying matches, totaling 36 minutes earlier this month. Arreaga made one appearance — a start against Paraguay on Sept. 2. Ecuador scored two goals after Arreaga substituted out of the match in the 59th minute.

Sounders wingback Brad Smith (Australia) and brothers Cristian (U.S.) and Alex Roldan (El Salvador) also returned to the starting lineup after being used as subs in the Minnesota match. That shifted Rowe from right wingback to central midfield with Joao Paulo.

The sides are familiar with each other, including the owners often vacationing together. Seattle announced this week an alliance with Orlegi Sports, the business arm that operates Santos, for charitable work in the Latinx community such as the COVID-19 vaccination clinic hosted by the teams at Sea Mar Museum of Chicano/a/Latino/a Culture in South Park.

On the field, the Sounders lost on aggregate scoring to Santos in the 2011-12 CONCACAF quarterfinals and 2012-13 CONCACAF semifinals.

Seattle will end its three-game stretch with an MLS match against RSL at Rio Tinto Stadium on Saturday. The Sounders are on a four-match win streak on the road.