Yurisbel Gracial hit the second grand slam of the game in the 12th inning Sunday to help the Fukuoka SoftBank Hawks earn a 12-8 walk-off win against the Seibu Lions and a series sweep to move within five games of the Pacific League leaders.

Prior to Gracial’s late heroics, Yuki Yanagita and Kenta Imamiya, who hit the game’s first grand slam, drove in a combined eight runs as the defending Japan Series champs won their ninth straight.

“I needed to hit in that situation and the fans’ support helped me get it done,” Gracial said of his fourth home run of the season. “It doesn’t matter who you are, any batter in that situation is going to find it hard to get a hit, but I tried to relax, hit the ball hard and bring in a run.

“Our pitchers did so well in nerve-wracking situations and it was a great team win.”

Kenichi Nakata (5-3) picked up his 100th career win after two scoreless innings of relief in which he fanned five for the second-place Hawks.

“I saw from the bullpen I could feel everyone’s will to win and I rode that emotion as I took the mound,” said Nakata. “Something like that (three strikeouts in the ninth) is luck, but I was able to execute my pitches well. This win belongs to the whole team, and this 100th win is one I’ll never forget.”

Yanagita opened the scoring at Yafuoku Dome, plating Gracial with a first-inning homer against Lions starter Kuo Chun-lin.

In the second, Kuo, the right-hander from Taiwan, issued two walks and hit a batter to land himself in a bases-loaded jam. Imamiya capitalized with a grand slam to left field to give the home team an early 6-0 lead.

Rookie SoftBank lefty Kotaro Otake gave up a leadoff homer to Sosuke Genda in the fourth, and Hideto Asamura drove in a run in the sixth before pinch hitter Tomoya Mori singled in the first of four Seibu runs in the seventh and tied it.

The Lions turned it around in the eighth, when righty Robert Suarez yielded a hit and a walk to put a runner in scoring position. Takumi Kuriyama dropped a go-ahead RBI single into right field, and Shogo Akiyama ripped one past first to make it 8-6.

But after Gracial’s leadoff single in the home half of the inning, Yanagita cranked his 30th home run of the year to keep the Hawks alive and send the game into extra innings.

In the top of the 10th, Ryota Igarashi got into a bases-loaded jam but struck out Genda to end the threat. Kyle Martin, who signed with the Lions in July from Triple-A ball, retired three straight in the bottom of the inning.

After Nakata struck out three straight in the 12th, Seibu reliever Hiromasa Saito (1-2) gave up two hits to put runners on second and third. Tatsushi Masuda took the mound and walked Imamiya to load the bases.

Gracial, who went 3-for-6, fouled off two pitches before connecting to the right field stands.

The Hawks’ win follows three-game sweeps of the Orix Buffaloes and the Hokkaido Nippon Ham Fighters, who were shoved down into third place.

Fighters 4, Eagles 2

At Sapporo Dome, Shinya Tsuruoka drove in three runs against lefty Takahiro Shiomi (2-3) and Hokkaido Nippon Ham’s early lead survived Hiroaki Shimauchi’s two-run RBI double in the sixth. Nick Martinez (9-8) fanned seven over six innings and earned the win.

Buffaloes 8, Marines 1

At Zozo Marine Stadium, Yuki Nishi (7-11) allowed a run over seven innings to beat Chiba Lotte, while Stefen Romero and Chris Marrero each drove in a run and scored one in Orix’s three-run third inning.

CENTRAL LEAGUE

Tigers 9, Giants 8

At Tokyo Dome, Kazuma Okamoto, Alex Guerrero and Casey McGehee all homered to put Yomiuri ahead, but Ryutaro Umeno’s two run shot against Hirokazu Sawamura (1-6) in the eighth sparked a six-run rally that earned Hanshin the come-from-behind win. Atsushi Nomi (3-2) picked up the win for pitching a 1-2-3 seventh and Rafael Dolis earned his 29th save.

Swallows 7, BayStars 3

At Jingu Stadium, Wladimir Balentien broke a 2-2, third-inning tie with his CL-leading 33rd home run, and Tokyo Yakult went on to beat Yokohama. Balentien became the 62nd player in Nippon Professional Baseball with 250 home runs.

Dragons 11, Carp 1

At Mazda Stadium, Dayan Viciedo and Shuhei Takahashi each hit two home runs, while Chunichi rookie Kento Fujishima (2-1) held Hiroshima’s high-powered offense to a run over seven innings.