STOCKTON -- With a national audience watching, the De La Salle High football team played its best game of the season.

The Spartans rolled past host St. Mary's-Stockton 40-13 on Friday in a game televised by ESPNU. The result came just a week after De La Salle (3-0) put its legendary unbeaten streak against Northern California competition in jeopardy in a narrow win over Serra-San Mateo.

"We were a soulless, gutless team last week, to be honest, and in a lot of ways the week before, too," De La Salle coach Justin Alumbaugh said.

"The reason why is we didn't practice well and we weren't coming together as a team. Serra woke us up and made our guys realize we're only as good as we practice.

De La Salle’s Kevin Griffin (32) celebrates after tackling St. Mary’s Demetrius Ferguson (5) for a loss of yards in the first quarter of their
De La Salle's Kevin Griffin (32) celebrates after tackling St. Mary's Demetrius Ferguson (5) for a loss of yards in the first quarter of their game on Friday, Sept. 13, 2013 at St. Mary's High School in Stockton, Calif., on Friday, Sept. 13, 2013. ( (Jose Carlos Fajardo/Bay Area News Group))

"We have a lot of potential, but if we don't practice well, we can be taken down by any of the teams that we're playing on our schedule."

The Spartans brought the intensity early against the Rams (2-1).

John Velasco scored on a 6-yard run on De La Salle's opening drive, and Jerek Rosales had three interceptions in the second quarter, helping the Spartans (3-0) cruise to a 26-0 halftime lead and run its unbeaten streak to 239 games.

Velasco rushed for 142 yards and two touchdowns. Sophomore Antoine Custer added 117 yards on the ground and had one touchdown rushing and one receiving.

"Everyone was shouting, everyone was having a good time, and we played better because of it," team captain Sumner Houston said.

De La Salle quarterback Chris Williams attempted just one pass in the first half, but it went to Marquis Morris, a state champion in the hurdles, for a 60-yard touchdown that gave the Spartans a 14-0 lead in the second quarter.

Rosales' first pick came on St. Mary's best scoring chance. He caught the ball on his own 7-yard line and returned it for a score. His second interception set up a 1-yard touchdown run by Velasco.

Though De La Salle lost three fumbles and had a pass intercepted, it didn't let St. Mary's into the end zone until eight minutes remained the game.

On paper, this game looked to be a potential upset. St. Mary's gave De La Salle one of its toughest games of 2012 before losing 21-13. The Rams also beat defending Division IV state champion Central Catholic-Modesto last week.

In its first two games, De La Salle wasn't the dominant machine that many have come to expect.

The defense struggled at times to hold down Clayton Valley Charter in DLS's season opener, and the offense was out of sync last week when the Spartans squeaked by Serra in San Mateo.