The last time USC's basketball team defeated the top-ranked team in the country was 44 years ago, and that span is still growing.

No. 1-ranked Arizona, aided by a rash of Trojans turnovers in the second half, rolled to a 73-53 win over USC on Sunday night in front of a crowd of 8,347 at the Galen Center.

The victory lifted Arizona's record to 17-0 overall and 4-0 in Pac-12 Conference play, while USC dropped to 9-7 and 0-3 in conference games.

BOX SCORE: Arizona 73, USC 53

The Trojans gave Arizona a handful for the first 15 minutes of the game, and USC led, 27-23, with about five minutes left in the first half.

But as Arizona's defense stiffened, USC hurt itself with poor ball control and the result was that the Trojans scored their fewest points so far this season.

USC had 18 turnovers — including 12 in the second half — compared with eight overall for the Wildcats.

"Eighteen turnovers is too many," USC Coach Andy Enfield said, adding that "we had some easy transition opportunities that we didn't convert."

Arizona "is such a good defensive team, you need to score those easy baskets," he said.

The Wildcats' scoring was led by T.J. McConnell, with the junior guard converting five of his seven three-point attempts and scoring 19 points overall.

Forward Brandon Ashley also had 19 points for Arizona.

Junior guard Byron Wesley led the Trojans' scoring with 18 points. Sophomore forward Strahinja Gavrilovic added 10 points and freshman guard Julian Jacobs had nine points.

Gavrilovic's three points on a layup and converted foul shot got USC to within five points of Arizona with about nine minutes to play. But the Wildcats effectively wore the Trojans down from that point on.

"They made the plays they needed to at the end," said USC senior guard Pe'Shon Howard, who scored four points.

"Arizona is a great team, number one in the country," Howard said. "We have to put together a 40-minute game."

USC hardly entered the game on a roll, coming off a 79-60 loss to Arizona State. The Wildcats came in having beaten UCLA on Thursday, 79-75, at Pauley Pavilion.

"I'm not happy," Enfield said. "But I'm proud of our effort. If we can give that kind of effort and energy, we'll be fine."

The last time USC knocked off the top-ranked team was in 1970, when the Trojans edged UCLA, 87-86.

USC's next game is against Utah on Thursday in Salt Lake City, while Arizona hosts Arizona State the same day.

james.peltz@latimes.com

Twitter: @PeltzLATimes