In the search for St. Louis University’s offense, Wednesday’s 77-57 win over Richmond provided a reminder of what drives the team’s scoring best: its defense.

In what could have been the 19th-ranked Billikens’ best defensive showing of the season — which is saying a lot for a team that plays defense better than just about everybody in the nation — SLU denied Richmond almost every thing in the first half, and that got the Billikens’ offense into a perfect rhythm. SLU opened up a big early lead and kept it there to extend its winning streak to 13 games.

“We were really selling in the first half on D,” said forward Dwayne Evans. “We didn’t have many turnovers, we shut down what they wanted to do on offense and put them in interesting situations.”

Interesting, indeed. First, the obligatory numbers: SLU has won 13 straight, the sixth-longest streak in the nation, and improved to 19-2, matching the best record ever for the program after 21 games. SLU is 6-0 in Atlantic 10 play and has won 35 of its past 39 games, 20 of its past 22 against A-10 opponents.

SLU’s aggressive defense on one end led to easy offense at the other end, whether it was drives to the basket or in-rhythm 3-pointers. SLU shot 53 percent from the field in the first half while holding Richmond to 23 percent shooting and just 21 points in the first 20 minutes. SLU had 16 points off turnovers in the first half, but there were plenty of other times when SLU got the ball after Richmond possessions that didn’t go into the book as turnovers but came after the Billikens forced Richmond into bad shots that never had a chance of going in.

“That’s what we depend on, our defense,” said guard Jordair Jett. “We look at it as a scoring option. I think we forced a lot of turnovers and played pretty good D.”

Pretty good? If not for some turnovers that led to easy Richmond baskets in the closing minutes, after the game was decided, SLU probably would have held Richmond to a lower shooting percentage than any of its Division I opponents this season. As it was, this was the third time in six A-10 games that SLU held an opponent to under 32 percent shooting. It was a season low in shooting for the Spiders (14-7, 4-2), who came in having won four straight.

The early difference? “I think the strength and their intensity, and we didn’t match it, to be honest with you,” Richmond coach Chris Mooney said. “We’ve seen teams as tall, as big, Florida, (North) Carolina, UMass. But I thought we didn’t match their intensity, for sure.”

In what could be an unprecedented event at SLU, Jett followed up a points-assists double-double against Duquesne last Wednesday with a points-rebounds double-double his next time out. He had 21 points and 10 rebounds, taking advantage of Richmond’s undersized guards to consistently grab rebounds.

“I always tell my bigs, I’ll help them rebound,” Jett said. “I helped out more on the glass tonight.

“It’s a little easier for me to get rebounds. They don’t expect me to crash the glass. It’s easier to get a point-rebound double-double. As long as we get the win, that’s all I care about.”

Evans also had a double-double, with 15 points and 10 rebounds, the first time SLU had two double-doubles in one game since Tommie Liddell and Barry Eberhardt did it against Liberty in 2008. Austin McBroom had 12 points and Rob Loe had 10 points.

The offense may be finally clicking — SLU shot 50 percent or better for the second straight game, the early signs of a trend — but the defense continues to shine.

“I thought we did a real good job defensively and were able to convert points off our defense in the first half,” coach Jim Crews said, “then we attacked gaps from an offensive standpoint. I thought we did a good job of being aggressive, moving the ball, using the floor, attacking things. It was a really good effort by our guys.”