SAN DIEGO -- After batting practice, Raul Ibanez didn't think the ball would be carrying at Petco Park on Saturday night.
He was wrong.
"In fact the wind was blowing in and I didn't think things were going to fly," Ibanez said.
Jamie Moyer (5-6) allowed two runs and four hits in seven solid innings and had an RBI single, improving to 16-7 in interleague play.
Mike Piazza, Ben Johnson, Eric Young and Mike Cameron homered for the Padres.
Both of Johjima's homers, his seventh and eighth, came off Chan Ho Park (5-4) on first pitches and highlighted two-run innings in the fourth and fifth. Johjima added a two-run double in the ninth for a career high four RBI.
Ibanez homered off Park in the fifth, and added his 16th of the season off reliever Brian Sikorski in the seventh.
"I was missing location with my fast ball," Park said. "The base hit from the pitcher hurt me a little bit along with the three home runs. I threw two fast balls hit for home runs hit on the first pitch."
The 43-year-old Moyer's hit came in the fourth and gave the Mariners a 3-1 lead. It was a single to right that scored Jeremy Reed after Johjima hit his first homer earlier in the inning.
"Every squirrel finds a nut," Moyer said of his first hit and first RBI since June 18, 2004, at Pittsburgh.
The Mariners built their lead to 5-1 with two runs in the fifth with Ibanez hitting his 15th home run, a 412-foot shot into the Padres bullpen in center and Johjima following one out later with his second of the night into the left-field bleachers.
Four of Johjima's eight home runs have come against the Padres. It was the rookie's first multiple homer game.
Ibanez completed his fifth multihomer game with his 16th in the seventh to make it 6-2 after Johnson hit his homer in the bottom of the sixth.
Piazza gave the Padres a 1-0 lead in the second with his 10th home run, a 401-foot blast into the third deck of the Western Metals Supply Co. building in left.
"I guess it's a hitters ballpark," Moyer joked. "Solo (homers) are really killers the way I look at it. I didn't think I threw as well as I did the last outing (one run in eight innings against the Giants). But I got outs when I needed them."
Eddie Guardado, who came on to relieve Moyer in the eighth was greeted by back-to-back homers by pinch-hitter Young and Cameron to pull the Padres to 6-4.
Seattle added three runs in the ninth on Richie Sexson's RBI single and Johjima's double. Johjima finished with a career high four-for-five and four RBI.
"We made a lot of mistakes to him tonight," Padres manager Bruce Bochy said. "We threw quite a few balls right in his wheel house. Give him credit. He's not missing them."
However, Johjima suffered a bruised left quad when he took a batted ball just above his shin guard from the bat of Johnson. Johjima is listed as day-to-day.
The Padres had opened the bottom of the ninth with four straight singles off J.J. Putz, the last by Josh Barfield to make it 9-5. However, Putz then struck out Josh Bard, Mike Cameron and Johnson with the bases loaded to end the game.
Piazza has 407 career homers, tying him for 40th on the all-time list with Duke Snider. ... The previous record for most home runs in a game at Petco Park was seven done twice, once on July 2, 2004 against Kansas City (Royals 2, Padres 5) and May 4, 2005 vs. Colorado in 12 innings (Rockies 3, Padres 4). ... The last time a Mariners pitcher had a hit and an RBI in the same game was Gil Meche on June 24th last year against the Padres at Petco Park. Moyer's last hit was a two-run single on June 18, 2004 ... 1B Sexson went 1-for-5 and is 2-20 against the Padres this season. ... Moyer has pitched into the sixth inning in 15 of his 16 starts. ... Park is 0-2 with a 12.20 ERA in two games against the Mariners this year.