Right-hander Yuki Koyama allowed a run in eight innings on Saturday as the Central League-leading Yomiuri Giants defeated the last-place Tokyo Yakult Swallows 4-2.

Koyama (6-1) allowed five hits and a walk, while striking out five as the Giants clinched a spot in the postseason. Yomiuri’s magic number to clinch its third straight CL pennant dropped to five.

The Giants took the lead in the first inning on a three-run home run by Leslie Anderson, his 11th, off right-hander Taichi Ishiyama (3-7) at Tokyo Dome.

“I’m satisfied with the home run and happy we could win and reduce our magic number,” said the first-year player from Cuba.

Koyama retired the first 12 batters he faced until Wladimir Balentien reached on an infield single up the middle that might also have been ruled an error on shortstop Hayato Sakamoto.

The Swallows then ran into bad luck. Yuhei Takai followed with a drive off the top of the right field wall. The ball had a chance to be caught, so Balentien advanced cautiously and was just able to sprint to third ahead of a throw. But Balentien’s uncertainty held Takai to a single, and when Kazuhiro Hatakeyama blistered a liner back to first base, Anderson snared it and tagged the bag to double off Takai.

Yakult got back in the game in the following inning, when Ryosuke Morioka doubled and scored on a single by Shingo Kawabata, although Giants captain Shinnosuke Abe homered in the eighth, his 19th of the seeason restoring Yomiuri’s three-run cushion.

The visitors brought the tying run to the plate in the ninth but only managed to put one run on the board off lefty Tetsuya Yamaguchi and Scott Mathieson, who faced five batters but got the final out to record his 29th save.

The Swallows’ defeat eliminated them from postseason contention.

Carp 3, BayStars 1

At Hiroshima’s Mazda Stadium, Yuya Fukui (4-4) allowed a run in six innings and Rainel Rosario’s RBI pinch-hit single broke a 1-1 tie in the bottom of the sixth as Hiroshima snapped a three-game losing streak with a win over Yokohama.

Tigers 7, Dragons 3

At Koshien Stadium, Randy Messenger (13-9) allowed two runs in six innings and Mauro Gomez went 4-for-4 with a double, a home run and three RBIs as Hanshin defeated Chunichi for its third straight victory.

PACIFIC LEAGUE

Lions 6, Hawks 5 (10)

At Seibu Dome, Yuji Kaneko and Takumi Kuriyama singled with no outs in the bottom of the 10th off Ryota Igarashi (1-2) and Ryota Wakiya singled home the winning run as Seibu defeated league-leading Fukuoka Softbank for the second straight day.

The Hawks have lost four straight.

Marines 4, Buffaloes 3

At Chiba’s QVC Marine Field, Toshiaki Imae singled in the tying run in the ninth and Yoshifumi Okada doubled in the game-winner as Chiba Lotte came from a run down in the ninth inning to knock off second-place Orix.

Eagles 3, Fighters 2

At Sendai’s Kobo Stadium, Hiroaki Shimauchi singled in the winning run in the ninth inning as Tohoku Rakuten came from behind to beat Hokkaido Nippon Ham for its fifth straight victory.

The fourth-place Eagles moved to within 6-1/2 games of the Fighters, who currently occupy the PL’s final playoff spot.