Putting the metal to the mettle, the University of Hawai'i pounded out a statement-making 18-2 softball rout of Fresno State last night at Rainbow Wahine Softball Stadium.

The game was stopped after 4 1/2 innings because of the Western Athletic Conference mercy rule.

Before 1,010, the largest crowd in the stadium's 10-year-history, the Rainbow Wahine struck the first blow in this three-game series between WAC rivals. Today's doubleheader starts at 2 p.m.

"It was so beautiful," said first baseman Tylene Tausaga, who clubbed two of the Rainbow Wahine's six home runs. "I wish we could have played two games. I'm ready to go right now."

Brandi Peiler, Kate Robinson, Alana Power and Katie Grimes also hit home runs for UH.

The Rainbows entered with the higher national ranking (No. 16 to the Bulldogs' No. 25) and the WAC lead. But that meant little against the four-time defending WAC champions, who have appeared in 22 consecutive NCAA Regional tournaments.

What's more, Robin Mackin is the Bulldogs' entire pitching rotation. The All-America entered with a 26-8 record, WAC-best 1.26 earned-run average and 286 strikeouts in 228 innings.

But on this night, facing the nation's top home-run-hitting team and against a heckling crowd led by 40 Warrior football players, Mackin was reduced to a cameo appearance. Mackin lasted 11 batters, exiting after allowing seven runs in two-thirds of an inning, the briefest start of her career.

Peiler blasted a three-run homer and Power added a two-run blast in the seven-run first inning.

Seven of the Rainbows' eight second-inning runs came on homers. Grimes hit a three-run homer and Robinson and Tausaga each contributed two-run drives.

The Rainbows increased their NCAA-leading total to 70 home runs.

Grimes' first career homer meant all of the Rainbows' starting position players have hit home runs this season.

"It felt good, because I was the only one in the lineup who hadn't hit one out," said Grimes, a freshman catcher.

Power said: "It was a great feeling. The girls did a phenomenal job. We were seeing the pitches well. The bats were hitting the ball right."

UH coach Bob Coolen was concerned because of the 13-day break since the April 7 game against New Mexico State.

To prepare for Mackin, whose riseballs reach speeds of up to 68 mph, the Rainbows took daily batting practice. Coolen also scheduled a scrimmage against Chaminade on Tuesday. UH closer Jessica Morton, who can throw a 65-mph riser, was "loaned" to Chaminade to pitch against the Rainbows in the scrimmage.

"We really worked hard on the foray of pitches we would see coming out of Mackin," Coolen said.

Tausaga said the Rainbows were patient against Mackin, whose change-ups had difficulty landing in the strike zone.

"We came out focused," Tausaga said. "We came out ready."

After the Rainbows loaded the bases against Mackin, Robinson hit a chopper that bounced over third baseman Ashley White for a two-run lead. Peiler's ensuing three-run homer set the tone.

"We kept looking at each other, going, 'Is this happening?' " Power recalled. "It was incredible, especially against Fresno, such a good team."

Tausaga, a senior, remembered the past struggles against the Bulldogs.

"The roles kind of switched," Tausaga said. "The other years, it was the other way around. Now it's a different story. The story is great for us right now. I'm loving it."

The cushion was more than enough for Robinson, who allowed four hits in five innings to improve to 13-0.

"It's easy to pitch when you have a 15-0 lead," Robinson said. "We've been practicing hard, and this is probably the best result we could have asked for."

Justine Smethurst is regarded as the Rainbows' ace. But after reviewing scouting reports, Coolen concluded the Rainbows needed to open with a pitcher with a more varied repertoire against the aggressive Bulldogs.

"They're a power-pitching, power-hitting team," Coolen said. "I wanted to mix it up and put Kate out there. She's fresh. Her pitches move."

Tausaga said it was difficult for the Rainbows to quell their anxiousness in the hours leading to the game.

"We've been thinking about this game since forever," said Tausaga, who went 3 for 3 with four RBIs. "They're definitely our rival. I don't want to start anything, but I want to be truthful. They hate us. Fresno hates us. It's a rivalry. We respect them as a team. We know every time we play them it's going to be a good game. Both teams are going to hit. They're going to bring the fire. We're going to bring the fire, too."

Reach Stephen Tsai at stsai@honoluluadvertiser.com.