Christian Carto hit the canvas, and the arena went quiet.

Almost 15 minutes later, the ring was, too.

The previously undefeated fighter from Philadelphia was stunned by an overhand left and took a hard fall in the second round against Mexican southpaw Victor Ruiz (23-10-1, 16 KOs) on Friday night at the 2300 Arena. He was taken out on a stretcher with a neck brace and oxygen mask.

Carto, 22, took the decisive punch with 1 minute, 56 seconds left in the second round. Carto was out for a minute or so but was responsive during the roughly 15 minutes between being knocked out and getting carried out and driven to Jefferson Hospital.

According to Carto’s brother, Frank, Christian was cleared at the hospital and discharged just after midnight.

Carto landed a handful of solid combinations in the first round and was putting up a competitive second round when he was surprised, hitting the canvas head-first.

“Carto was in control of the fight, and he walked into a perfect shot,” said fight promoter J Russell Peltz. “His head banged into the floor and that was it. It happens.”

Carto’s camp rushed into the ring after the ref waved his arms without so much as issuing a count, and event staff waved for medics to come into the ring as Carto was unconcious. A few minutes later, a stretcher was brought in as the crowd stayed silent.

In his last fight, Carto beat 31-year-old Pedro Antonio Rodriguez (15-23, three KOs) of Mexico by unanimous decision at the SugarHouse Casino in November.

Carto moves to 17-1 with 11 knockouts.

Peltz sees a long road back for Carto.

“He has to decide what his future is, and he’s going to have to take at least, in my opinion, six months off, at least before he should fight, or even spar again with a knockout like that,” Peltz said.

Darmani Rock, the fight’s co-feature, beat Steven Lyons by knockout with 1:20 left in the fourth round. The Germantown heavyweight remains undefeated (14-0, nine KOs), while Lyons moves to 5-4 (two KOs).

The other results are as follows:

Welterweight Marcel Rivers beat Derrick Whitley in a six-round bout by unanimous decision.

Bantamweights Alejandro Jimenez and Edgar Joe Cortez fought to a draw in six rounds.

Sonny Conto defeated Jimmie Levins by technical knockout in the first round.

Bantamweight Jonathan Torres beat Dallas Holden in a four-round unanimous decision.

Lightweight Gerardo Martinez won a four-round split decision over Osnel Charles.