PULLMAN, Wash. — Nic Grigsby ran for a career-high 189 yards and Arizona beat Washington State 59-28 today to become eligible for its first bowl game in a decade.

Xavier Smith scored two touchdowns for Arizona (6-3, 4-2 Pac-10), which piled up 531 yards — including 317 on the ground — against the nation's worst defense.

Washington State (1-9, 0-7) actually played one of its better games in what has been a horrific year. But the Cougars still became the first Pac-10 team to give up 500 points in a season, with three games left to play. They have lost six straight and have given up at least 52 points in five of them.

The Cougars came in averaging only five points in conference games, and had not scored more than 17 points against a major college team. Their only win was 48-9 over Portland State, a FCS team

Arizona coach Mike Stoops had been on the hot seat in his fifth season, but the Wildcats appear headed to their first bowl game since 1998.

Grigsby, who rushed for a career-high 186 yards versus WSU as a freshman last year, ran 28 times.

Washington State scored first — taking its first lead of the season in a Pac-10 game — when Dwight Tardy took a pitch from Kevin Lopina and galloped 18 yards with 10:10 left in the first. The touchdown also broke a streak of 10 straight quarters in which the Cougars had been shut out.

Arizona replied with a 12-play drive and Mike Thomas ran 5 yards for a touchdown to tie the game.

Tight end Rob Gronkowski caught a short pass from Willie Tuitama and ran 43 yards for a touchdown to put Arizona up 14-7 at the end of the first quarter. Tuitama completed 11 of 15 passes for 214 yards.

After getting the ball on their own 46 to start the next drive, WSU's Logwone Mitz tore off runs of 8 and 42 yards to take the ball to Arizona's 4. Lopina ran it in to tie the score at 14.

Arizona replied with an 81-yard drive with Keola Antolin running 5 yards up the middle for a 21-14 lead with 10:20 left in the half.

The WSU offense stalled the rest of the half.

Meanwhile, Tuitama ran in from the 4 on a broken play for a 28-14 Arizona advantage. Arizona's Devin Ross intercepted Lopina on the next series, and Grigsby ran it three times, the last for a 6-yard touchdown and a 35-14 halftime lead.

Arizona's Smith scored on a 6-yard run on the opening drive of the second half for a 42-14 lead.

Mitz scored from 3 yards out on the next series to bring WSU to within 42-21.

The Cougars are last in the nation in defense, allowing 49 points per game, and second to last in offense, scoring just 12 a game. They have given up 502 total points this season, eclipsing the Pac-10 record of 469 set by Oregon State in 1981.