It was, teen phenom Efrain Alvarez proclaimed, “my best moment here at the LA Galaxy,” but that didn’t mean he avoided a little ribbing.

The 16-year-old midfielder netted his first two goals with LA’s first team Wednesday night, putting away a splendid free kick 10 minutes into the second half and tapping home a feed from Favio Alvarez six minutes after that as the Galaxy roared into the fifth round of the US Open Cup with a dominant victory over amateurs Orange County Football Club.

Rookie Emil Cuello also tallied his first goal with the Galaxy’s top side to complete a 3-0 triumph before a full house at Dignity Health Sports Park’s track and field stadium, one that came fairly easy but not as simple as it might have.

LA, aiming for its third crown in the oldest soccer competition in the United States and first since a surprising 2005 MLS Cup/Open Cup “double” in 2005, might have scored six or seven or eight with a bit more fortune and precision, but the best chances — the goals aside — went off-target again and again.

The Galaxy behind winger Emmanuel Boateng’s speed on the left, teenage right back Julian Araujo’s crosses from the right, and Favio Alvarez’s ability to carve up defenses and feed teammates with dangerous balls had nearly all of the first 45 minutes but couldn’t find the net.

Not that they were particularly concerned.

Efrain Álvarez and Favio Álvarez combined for 2 goals and 2 assists as @LAGalaxy won 3-0 to end the dreams of amateur side @ocfcsoccer | #USOC2019

The Galaxy will learn their Round of 16 opponent via the Official Draw tomorrow at 10 AM ET on @opencup & https://t.co/PMU8idFRux pic.twitter.com/vWjtHlNQMY — U.S. Open Cup (@opencup) June 13, 2019

“We weren’t clinical enough in the first half and put it away …,” center back Daniel Steres said. “Stay the course [was the halftime message]. We knew we just had to be clinical, put one in, and it would break them. And that’s what happened.”

It sends the Galaxy to next week’s Round of 16 match on the road against the Portland Timbers. The date, time and venue is still to be determined. The winner of that game will play either the San Jose Earthquakes or Los Angeles FC.

Not surprisingly, Galaxy superstar Zlatan Ibrahimovic was not part of the 18-man roster. With Sebastian Lletget injured, Jonathan Dos Santos and Uriel Antuna away on international duty with Mexico, and Giancarlo Gonzalez not on the roster, the Galaxy had to rely on some younger players to defeat an amateur side. Players like Alvarez, Araujo and Cuello, took advantage of their playing time.

Orange County, a National Premier Soccer League team from nearby Lake Forest, was this Cup’s Cinderella. Coached by former Galaxy (and National Soccer Hall of Fame) defender Paul Caligiuri, OCFC knocked off two USL Championship sides — Orange County Soccer Club and the Eric Wynalda-coached Las Vegas Lights — to reach the fourth round, the only amateurs to do so.

They created a handful of chances, the best by Dakota Collins, Peter Gregory and Rayan Holland, but couldn’t beat David Bingham. And when the Galaxy’s goalkeeper stumbled — he dropped a cross in the 86th minute, leading to Holland’s shot from just beyond the 6-yard box — he had protection. Perry Kitchen cleared that one off the line.

By then it was 2-0. Efrain Alvarez, a highly regarded local product who plays for Mexico’s U-17 national team, buried his 55th-minute free kick after Boateng drew a foul at the edge of the OCFC box, and his blast to the lower-left corner left goalkeeper David Preys no chance.

The second goal, in the 61st, came after a series of Orange County miscues as the Galaxy applied heavy pressure on Preys and his backline. A couple of errant passes left center back Joshua Davis alone, and when his first touch betrayed him, Favio Alvarez swooped in to take the ball, race past and confront Preys.

He dropped a little pass to the right, and Efrain Alvarez tapped it into an open net. He was ecstatic.

“It was a once-in-a-lifetime feeling that you can’t compare with any other …,” he said afterward. “I can’t explain how happy I am, but I;m happier that we qualified for the next round.”

He might have completed the hat trick but fired wide from good spots in the 73rd and 82nd minutes and didn’t get enough on a close-range shot in the 88th.

“A hat trick? I think he should have had six,” Steres joshed. “I don’t know what he was doing out there.”

Said Cuello: “I think he could have had at least four or five, but he was able to get two, and that’ll give him some confidence going on.”

Boateng should have netted two in the first half — he went wide with open shots in the goalmouth in the first and 13th minutes — and Joe Corona came close from about 25 yards in the 32nd. Favio Alvarez had myriad chances, mostly firing high. He hit the crossbar midway through the second half.

Cuello tallied in the 90th minute, taking a feed from Favio Alvarez and burying it into the lower-right corner. It was amends after he didn’t get a shot off on the sequence two minutes earlier.

“Feels great to get the first one out of the way,” said the Argentine-born midfielder, who was drafted out of SMU. “[Earlier I had a] clear chance for goal. I was pretty disappointed in myself that I didn’t shoot it, so the next one I got, I was, like, I got to shoot and put it away.”

The Galaxy held 72 percent possession and outshot their foe, 24-6, but put only eight shots on frame (to two by OCFC).

Caligiuri wasn’t pleased with the call that led to Efrain Alvarez’s free kick, nor with the mistakes that enabled LA to make it 2-0 with “a soft goal.” He thought the Galaxy were “better” and “stronger” in the first half, when they created more chances rather than feasting off fouls and miscues.

But the experience meant a lot to his team, an assortment of college players, others aspiring to turn pro, and several who work normal jobs and had to battle traffic to Carson after their shifts ended.

“Mixed emotions right now,” he said. “Obviously the run to get to the fourth round of the U.S. Open Cup for an amateur team is huge, and we held the Galaxy to a nil-nil draw in the first half. We kind of opened things up to try to go for the win in the second half.

“At the end of the day, it didn’t work out — [the Galaxy] were a better team and more organized and more physical — but out guys never gave up, and I think there were some unfortunate breaks that didn’t go our way, but we know that’s soccer, right? … My guys are happy. They were very happy to come play against the Los Angeles Galaxy, and we’ll move on.”

The game ended on a sour note. Bingham was hit hard and late by Michael Bryant after snagging an OCFC free kick into the Galaxy goalmouth in the first minute of stoppage. Steres went after Bryant, pushing him, and Bingham appeared to slug him. Referee Alejandro Mariscal showed Bryant a yellow card.

“You don’t want to see that,” Steres said. “It’s definitely a cheap shot. … He knew what he was doing. He was smiling. He knew exactly what he was doing. There’s no place for that in the game.”

Caligiuri said he didn’t think Bryant, who’s training to become a firefighter, was trying to hit Bingham.

“I don’t think it was one player trying to contest the goalkeeper,” he said. “There were a lot of bodies. It wasn’t just one player contesting the goalkeeper. I think there were a lot of players there, ion both teams. The guy’s going to be a firefighter. He’s a first responder [on an emergency crew]. I don’t think he’s trying to hurt anybody. That’s not his mentality, that’s not the way he thinks.

“But what happened afterward I think it uncalled for.”