Shun Yamaguchi threw two-run ball over eight innings and the Yokohama BayStars broke out the bats to wallop the Yomiuri Giants 10-2 for their first victory of the 2015 regular season on Saturday afternoon.

Takayuki Kajitani went 4-for-5 with three RBIs and Jose Lopez hit a two-run homer in the 12-hit onslaught. Yamaguchi scattered six hits, struck out eight and walked two in front of a crowd of 42,369 mostly Giant fans at Tokyo Dome.

“Everyone contributed, truly a team effort. It was definitely better than we expected,” said BayStars skipper Kiyoshi Nakata, whose team lost 3-2 to the Giants on Opening Day the previous night.

Giants starter Aaron Poreda, who went 2-1 with a 5.91 ERA in 26 relief appearances with the Texas Rangers in 2014, got his baptism to Japanese baseball in the first before the lefty settled down to strike out the side in the next inning.

Yokohama leadoff man Takehiro Ishikawa drew a walk, stole second, and reached third on a sacrifice bunt. Kajitani then doubled down the left-field line for a 1-0 lead.

Kajitani stole second and came around when trying to steal third as Giants catcher Seiji Kobayashi threw the ball into the outfield for an error.

“Yesterday they scored against us first so I wanted to get on the scoreboard first today,” said Kajitani, who has six hits in his first two games. “I’m doing better than I’d hoped. I don’t want to get carried away, too early.”

Aarom Baldiris lined a two-out RBI double to the gap in left-center for Yokohama’s third run. Poreda yielded back-to-back, one-out hits in the third and a sac fly by former Giants first baseman Lopez that made it 4-0.

The BayStars opened the flood gates in the five-run sixth, surrendered a two-run double by Kajitani and Lopez’s line drive over the left-field wall with a runner on first off reliever Mizuki Tsuchida.

“I didn’t feel anything in particular,” said Lopez after homering off his former team. “I’ve been prepared since spring training in Okinawa. I was looking for a fastball away and he threw a (2-1) slider. I got a chance to use my hands.”

Yamaguchi had a lapse when he juiced the bases in the sixth and surrendered a bases-loaded walk to Yoshinobu Takahashi and an RBI groundout to Yoshiyuki Kamei, but the damage was negligible.

Yoshitomo Tsutsugo, who was 4-for-4 with two RBIs, rubbed salt in the wound with his ninth-inning, leadoff blast — his second home run in as many games.

“It was nice to hit a home run, but I didn’t know it was gone until after I hit it,” Tsutsugo said.

Carp 1, Swallows 0

At Hiroshima’s Mazda Stadium, former Minnesota Twins lefty Kris Johnson (1-0) tossed a one-hit shutout with seven strikeouts and no walks in his Japan debut as Hiroshima beat Tokyo Yakult for its first win.

Tigers 1, Dragons 0 (10)

At Osaka’s Kyocera Dome, Hanshin got its second straight walkoff victory over Chunichi when Kentaro Sekimoto was hit by a pitch with the bases loaded in the 10th inning.

PACIFIC LEAGUE

Hawks 4, Marines 2

At Fukuoka’s Yafuoku Dome, Seiichi Uchikawa delivered a go-ahead two-run single in the third inning off Chen Kuan-yu (0-1) and added a fifth-inning RBI single as Fukuoka Softbank rallied over Chiba Lotte to get in the winner’s column in 2015.

Lions 2, Buffaloes 0

At Tokorozawa’s Seibu Prince Dome, Ryoma Nogami (1-0) allowed three hits over seven innings and Hideto Asamura opened the scoring with a sac fly off Bryan Bullington (0-1) in the first as Seibu shut out Orix for the second day in a row.

Eagles 4, Fighters 2

At Sapporo Dome, Kenny Ray (1-0) allowed one run over five solid innings and Kazuya Fujita drove in a pair of runs off Hokkaido Nippon Ham’s Masaru Takeda (0-1) to lift Tohoku Rakuten to its first win.