GREENVILLE, N.C. -- A battle of dual-threat quarterbacks for a half quickly turned one-sided on Saturday, and the result was a decisive win for No. 18 South Florida.

The Bulls, behind versatile senior quarterback Quinton Flowers and an aggressive defense, turned in a dominant second-half performance Saturday afternoon in rolling to a 61-31 American Athletic Conference victory over East Carolina.

Flowers passed for 160 yards and a touchdown and added 93 yards on the ground and another score as the Bulls (5-0, 2-0 AAC) extended their winning streak to 10, the nation's third-longest.

Graduate transfer quarterback Thomas Sirk kept the Pirates (1-4, 1-1) in it for a half, as ECU trailed 31-24 at the break. Sirk rushed for 75 yards on 11 carries in the first half but was held to 12 yards on six carries in the second. He completed 20 of 43 passes for 302 yards with a pair of touchdowns and two interceptions.

"The key thing is we had to stop the quarterback run," South Florida head coach Charlie Strong said.

"It was the reason they were able to drive the ball. ... Any time a quarterback runs it, you have to stop the downhill run. That's what we weren't doing the first half. We made the adjustment at halftime and came back out and stopped it."

The Pirates had no answer in stopping the Bulls.

South Florida eclipsed 30 points for the 22nd straight game -- and did it by halftime -- and is just one game shy of Oregon's all-time record in the AP Poll era (1936).

ECU, with its 30-7 deficit in the second half, has been outscored 129-52 after halftime this season and has given up at least 56 points in three of five games.

USF rushed for 390 yards on its way to a total of 575 yards. ECU has allowed at least 575 in all five of its games this season.

"What you saw today is we have a long way to go to get to the top of this conference," said ECU second-year head coach Scottie Montgomery.

"We see what the top of the conference looks like. It is fast and it is big, but we need to handle what the Pirates need to handle, and that was mental errors, dropped balls, missed tackles, or tackles that we just got ran over a couple of times."

Flowers worked his magic in eluding tacklers while D'Ernest Johnson and Darius Tice provided a physical one-two combination in the backfield. Johnson rushed for 111 yards on 16 carries and scored a pair of touchdowns, becoming the 11th 100-yard rusher in the last nine games against ECU. Tice had 65 yards on 12 carries and also scored a touchdown.

Receiver Marquez Valdes-Scantling provided yet another threat, catching six passes for 94 yards and a touchdown. He also gained 80 yards on two carries, including a 75-yard score on a jet sweep.

"I'm so happy to see it happen," Strong said of the production from the 6-foot-5 Valdes-Scantling. "He only had the one drop on the sideline, but to make the catches he made -- those were tough catches. He went and got it."

USF's defense, after giving up 279 yards in the first half, limited the Pirates to 133 in the second half. The Bulls came up with a pair of interceptions for the fifth straight game, giving them a nation-best 14 and 16 takeaways overall.

Auggie Sanchez's 43-interception return off a tipped pass gave the Bulls a 21-10 lead in the first quarter.

"One of the most pivotal plays of the game was the dropped ball, pick for a touchdown," Montgomery said. "There was a lot to that play that should have been an easy completion. It was a big change in momentum."

The lead grew to 24-10 on a 37-yard field goal by Emilio Nadelman at the 12:13 mark of the second quarter, but the persistent Pirates hung around.

Sirk converted a fourth down with an 11-yard pass to Davon Grayson, then capped a nine-play, 75-yard drive with a 13-yard run to make it 24-17.

Valdes-Scantling streaked 75 yards on a jet sweep on the Bulls' next play for a 31-17 lead, but ECU consumed the final 5:01 of the half and scored on Sirk's 3-yard jump pass to tight end Stephen Baggett as time expired.

Flowers, who was just 2-of-7 passing for 42 yards in the first half, heated up early in the second, connecting on six of his first seven passes for 90 yards in directing two scoring drives. He zipped a 14-yard pass to Tyre McCants for a 38-24 lead, then answered ECU's only second-half score with a 4-yard pass to Valdes-Scantling.

NOTES: Saturday's attendance of 34,883 was the lowest for an ECU regular-season home game since 2006. ... USF QB Quinton Flowers had 253 total yards to give him 9,042 for his career. ... ECU is 2-13 in its last 15 games, with both wins coming against UConn. ... The Pirates have scored in 247 consecutive games, the 11th longest streak in the nation. ... USF rushed for 390 yards, compiling at least 150 yards for the 23rd straight game, the longest streak in the nation. ... ECU is just one of four FBS teams with three active receivers with at least 100 receptions after Saturday's game -- Davon Grayson (106), Jimmy Williams (100) and Quay Johnson (100).