The Huskies overcame late pushes from Hawaii and offensive problems late in the game, when their best accomplishment was running out the clock.
Mercer Island High School product Jeff Lindquist threw for 162 yards in his first start for Washington after Cyler Miles was suspended for the game for his role in an offseason fight. But most of Lindquist's total came on the big play to Ross. He was 3 for 15 in the second half for 28 yards.
The Huskies punted on eight of their first nine possessions in the second half, but the Rainbow Warriors were unable to take advantage of the opening. Hawaii managed two field goals for the only scoring in the second half.
Washington's defense improved after struggling early and spotting Hawaii a 10-0 lead on its first two possessions. The Rainbow Warriors lost the advantage in one quick second-quarter burst, turning the ball over on downs and then allowing the Huskies' second-longest pass play in school history.
Hawaii's Joey Iosefa rushed for 143 yards and a touchdown. Lavon Coleman had 87 yards rushing for Washington.
Both of Washington's touchdowns came after Hawaii mistakes. First, Hawaii's Ne'Quan Phillips lowered his right shoulder and hit Lindquist in the chest well after a throw on a fourth-and-9 play, setting up Ross' 20-yard reverse for the first Huskies' touchdown.
Hawaii turned the ball over on downs later in the first half on a trick play, with Marcus Kemp throwing a pass on a reverse that fluttered 2 yards short of tight end Harold Moleni in the end zone.
On the next play, Lindquist threw the ball 55 yards in the air to Ross, who covered the rest of the field himself. It was the longest play for Washington (1-0) since Jake Locker connected with Marcel Reece in 2007 for 98 yards.
The Rainbow Warriors (0-1) missed another chance to tie it or get closer just before halftime when Ikaika Woolsey overthrew Kemp streaking toward the end zone, and then Tyler Hadden missed a 40-yard field goal off the left upright.
Woolsey threw for 207 yards while running a scheme that included several trick plays. Iosefa had a 1-yard TD on Hawaii's first possession.
Petersen was hired by Washington in December after eight seasons in charge at Boise State, where he compiled a 92-12 record, made bowl games each year and finished in the rankings six times.
The Huskies return to action Saturday when they face Eastern Washington. Kickoff is scheduled for 1pm at Husky Stadium. It's a game you can listen to live on KOMO NewsRadio.