By midway through the first half Saturday, the George Washington men’s basketball team’s only points had come on a rebound tapped in by a La Salle player. The Colonials had clanked two free throws, missed an uncontested dunk, given away the ball 10 times and burned two timeouts.

It got worse before it got better and the Colonials slumped out of Tom Gola Arena with a 63-50 defeat, shattering their winning streak at six.

In their worst performance in almost two months, the Colonials (12-4, 2-1 Atlantic 10) got stuck at the start of each half, fell behind 19-2 and committed a season-high 20 turnovers — 15 by veteran players.

“They just jumped all over us,” GW Coach Mike Lonergan said. “We couldn’t even run an offense. Sometimes you can overcome one guy not playing well, two guys, but the amount of turnovers was incredible.”

The margin of victory was deceiving. The Explorers (9-7, 1-2) never trailed, were ahead by 14 at intermission and did not allow the lead to slip to less than 11 in the second half.

Kevin Larsen, the centerpiece of a usually reliable four-junior starting lineup, had the roughest outing, failing to score and committing six turnovers. Guards Joe McDonald and Kethan Savage combined for nine giveaways. GW’s only bright spots were sophomore Nick Griffin, whose three three-pointers in rapid succession provided a glimmer of hope in the first half, and freshman Yuta Watanabe (12 points).

“Their defense was great,” Lonergan said, “but you usually wake up after a few silly turnovers.”

Sophomore guards Jordan Price, an Auburn transfer, and Cleon Roberts scored 20 and 15 points, respectively, as La Salle defeated GW for the sixth time in the teams’ past seven meetings in Philadelphia.

The Colonials, picked to finish second in the Atlantic 10, had sweated out their first two league encounters, defeating Saint Joseph’s and Saint Louis by a combined seven points. And the latest affair got off to a turbulent start with turnovers on the first four possessions and five of the first six.

GW’s first basket — and only one for more than 12 minutes — was credited to Patricio Garino, whose miss in the lane was redirected into the net by La Salle’s Steve Zack.

“The pressure was on us the entire time, and we couldn’t get into the offense,” McDonald said. “It took us out of our game, and that was wrong on our part. We should have stuck to our game plan. They came out hard, came out strong from the get-go and didn’t let up.”

The defense, so ragged in the first half against Saint Louis on Tuesday, allowed numerous open shots. When a turnover led to a transition basket and 12-2 deficit, Lonergan called his first timeout. It did not help. Garino had a clear path to the basket but took off too early, missing the dunk and landing on his back, eliciting howls from the crowd of 2,041.

The turnovers and margin continued to grow. GW’s first true field goal came with 7 minutes 45 seconds left before halftime on John Kopriva’s hook shot. Griffin sparked a brief recovery, but the Colonials began the second half by committing two turnovers and conceding two easy baskets. Less than two minutes into the half, Lonergan begged for another timeout.

“Our guys did what we wanted exactly perfectly,” Explorers Coach John Giannini said. “They did it with great effort. They had an edge.”

The Colonials had neither an edge nor anything else working after halftime, making one field goal in 9 1/2 minutes. Free throws prevented an early blowout, but GW was not doing enough defensively to dent the margin.

Midway through the half, sparked by Garino (nine points) and Watanabe, the Colonials made their first genuine push. The Explorers, though, were not rattled.

“They exposed a lot of our weaknesses,” Lonergan said. “Hopefully it’s a one-game thing.”