EUGENE -- One of the most-discussed topics of Oregon's offseason was the ending of a longstanding custom that allowed fans who left Autzen Stadium to re-enter later.

The new policy reduced the halftime exodus for parking-lot tailgating during Saturday's season-opening victory over Bowling Green, and spectators were largely in their seats for the third-quarter kickoff.

But there was another stark change taking place on the field, too: The Ducks had also decided to show up for the start of the second half.

In Saturday's third quarter, Taj Griffin took a screen pass 83 yards for a touchdown, safety Ugo Amadi returned an interception 38 yards for another score, and Amadi ended the next Falcons drive with a sack to force a three-and-out. Those plays opened a comfortable lead that ended in a 54-28 victory and UO's 14th consecutive win in a home opener.

For a program that struggled through a string of anemic third-quarter performances in 2017, it was welcome progress -- even if it also is a small sample size.

"A huge point of emphasis for us over the summer," coach Mario Cristobal said, "was making sure that we start the second half quickly."

Compared to last season, UO only had room to improve.

Under coach Willie Taggart, Oregon generally started fast and held on late. It finished with scoring margins of plus-27 in first quarters, plus-76 in second quarters and plus-29 in fourth quarters.

In third quarters, however, Oregon was outscored by 41 points. It averaged 4.0 points, which ranked 103rd nationally, while allowing 9.2 points defensively, which ranked 116th. If opponents started quickly after halftime, UO often had no answer. Seven times last season the Ducks failed to score a point in third quarters, and five of those games resulted in losses.

Warning signs came with 2017's first three weeks. Against Nebraska and Wyoming, UO scored more than 40 points by halftime and built large leads only to appear to be a wholly different team after halftime. In those instances, offensive coordinator Marcus Arroyo said, UO was often "trying to avoid the mental lapse" but struggled nonetheless.

"We saw that dip in the third quarter last year," Arroyo said. "We definitely focused on turning the scoreboard off and teaching our guys the score will take care of itself and executing is really going to be the most important part."

The 23rd-ranked Ducks' scoring margin so far in 2018 is plus-seven, and Saturday's nonconference matchup against Portland State (0-1) could allow that to grow. The Vikings were outscored 42-0 after halftime of their season opener, against Nevada. Players and coaches offered no profound steps the program has taken to improve its efficiency after halftime, saying it was a confluence of getting better at doing football's "little things."

"I don't know if there's anything you can specifically do for it other than just talk about it and be aware of it and know that you need your best effort in the second half," quarterback Justin Herbert said.

Tight end Jacob Breeland cited better discipline under Cristobal, and "not making dumb mistakes." Receiver Jaylon Redd believed Saturday's effort was the byproduct of more consistent effort in practices.

"We want to prove everyone wrong, that we can do what we can do in the first half in the second half, because last year we weren't able to get that job done," Redd said.

Oregon's quick start to the second half mitigated a clumsy beginning in the first quarter. UO trailed 10-0 after the first 10 minutes. But in that deficit, the Ducks also saw growth from 2017.

The largest hole UO rallied from to take a lead last season was also 10 points, against Arizona State, but that late comeback was spoiled by ASU's game-winning scoring drive in the fourth quarter.

After falling behind against Bowling Green, UO scored 37 consecutive points.

"It's just so encouraging to see our guys respond after a slow start, come from behind and score 30 in the second quarter," Arroyo said. "That's a sign of a good team that's resilient and can continue to turn the scoreboard off and keep playing ball."

-- Andrew Greif

agreif@oregonian.com