USC, Steve Sarkisian appear big winners in national signing day

National signing day could not have gone better for USC.

New Coach Steve Sarkisian and his staff closed with a flourish as three top Southland players announced Wednesday that they would become Trojans.

Bellflower St. John Bosco lineman Damien Mama, Gardena Serra cornerback and receiver Adoree’ Jackson and Long Beach Poly receiver and defensive back John “Juju” Smith said during news conferences at their schools that they were headed to USC.

Euphoria pulsated through USC’s McKay Center and on Trojans-related message boards as the announcements were made.

But when Sarkisian met with the media in the afternoon to formally announce a 19-player class, USC was still waiting on a signed letter of intent from Jackson.

NCAA rules prohibit coaches from speaking publicly about recruits who have not signed scholarship agreements or enrolled in school.

“I’m confident, in the situation that we’re in, that it’s going to be favorable for the Trojans,” Sarkisian said.

Serra Coach Scott Altenberg said early Wednesday night that Jackson’s parents had not yet signed the letter of intent, but he expected Jackson would become a Trojan.

About 8 p.m., USC officially announced Jackson as a member of the class.

“Adoree’ is just a fantastic athlete,” Sarkisian said in a statement on USC’s website. “He is extremely explosive with amazing balance.”

The announcements by Mama, Jackson and Smith sent a class not previously ranked in the top 30 by Rivals.com to No. 10 nationally.

“That’s a home run,” said Mike Farrell, national recruiting analyst for Rivals.com.

Greg Biggins, national recruiting analyst for Fox Sports and Scout.com, said the Trojans’ class ranked No. 1 in the Pac-12 Conference and 10th nationally.

Even with the few hours of uncertainty surrounding Jackson, it was a far different vibe than in 2013, when numerous players who had announced commitments to the Trojans changed their minds and signed with other schools.

Sarkisian has been on campus for only two months and his staff was not completed until two weeks ago.

But the class they recruited — the final one under NCAA sanctions — addressed several needs, particularly on the offensive line, and also featured several dynamic two-way players.

Sarkisian indicated that he did not know Jackson’s and Smith’s decisions before they made their announcements.

“I used to say, ‘If you don’t know before they announce, that’s not a good sign,’” Sarkisian said. “But I can honestly say today that theory got thrown right out.”

Sarkisian was particularly pleased with the five offensive linemen.

Toa Lobendahn and Jordan Austin graduated early from La Habra and Claremont, respectively, and they are taking classes at USC and will participate in spring practice. They will be joined in the fall by Mama, Chris Brown of Loyola and Viane Talamaivao of Corona Centennial.

“You could put this O-line class up against any other O-line class in the country,” Sarkisian said after the news conference. “I think these guys are that good.”

The class also includes seven players who could be receivers or defensive backs.

“If you can excel on both sides of the ball, that gives us versatility moving forward,” Sarkisian said.

Smith, Ajene Harris of Crenshaw and Rahshead Johnson of Long Beach Cabrillo will get their first opportunities on offense, Sarkisian said. Jonathan Lockett of Santa Ana Mater Dei, John Plattenburg of Houston Lamar and Lamont Simmons of Jacksonville (Fla.) Raines will get their first opportunities on defense.

Other signees Wednesday: defensive lineman/linebacker Malik Dorton of Bellflower St. John Bosco, tight end Bryce Dixon (Ventura St. Bonaventure), linebackers Olajuwon Tucker (Serra) and Uchenna Nwosu (Harbor City Narbonne).

Quarterback Jalen Greene (Serra) and defensive linemen Don Hill (Boise, Idaho, Timberline) and Claude Pelon (Mesa, Ariz., Community College) are attending classes at USC and will participate in spring practice.

gary.klein@latimes.com

Twitter: @latimesklein

Times staff writer Eric Sondheimer contributed to this report.