The Seibu Lions clinched their 22nd pennant in franchise history on Sunday, but did so in unusual fashion by both leading the Pacific League from wire to wire and becoming the second championship team to finish last in the league in ERA.

The Lions nailed it down when their closest rivals, the second-place SoftBank Hawks lost in Fukuoka and represented a repeat of the Lions' 2008 championship -- also celebrated at Sapporo Dome due to another team's defeat elsewhere.

"It wasn't ideal, but in the end, winning is what matters," Lions manager Hatsuhiko Tsuji told Kyodo News at MetLife Dome outside Tokyo on Friday.

The Lions have outscored every other team in Nippon Professional Baseball in this season, and even with five games remaining to play are one of the top-five highest scoring teams in history. And despite the club's league-worst ERA, the Seibu pitching staff boasts three reliable starters, and engineered a bullpen upgrade in the middle of the season that allowed the offense to have such a huge impact on the pennant race.

The Lions' race to their first pennant in 10 years, ending the franchise's second-longest championship drought, finished the way it began -- with a long winning streak. Seibu opened the season with eight straight wins, and rode the tide of a 12-game win streak to lower their magic number to one on Friday.

Center fielder Shogo Akiyama, first baseman Hotaka Yamakawa and second baseman Hideto Asamura are having MVP-caliber seasons, and the Lions' offense is deep and consistent.

The team ranks No. 1 in the PL in OPS (on-base percentage plus slugging average) among starting catchers (Tomoya Mori), first basemen, second basemen, third basemen (six-time home run king Takeya Nakamura having a comeback season), shortstops (2017 rookie of the year Sosuke Genda) and right fielders (Shuta Tonosaki). Akiyama is second in OPS in center field behind SoftBank Hawks star Yuki Yanagita.

When Mori catches and Ernesto Mejia bats as the designated hitter, the Lions have six legitimate home run threats in the lineup.

"That's fun to be a part of that," Mejia said. "I feel sorry for their pitchers."

Because Mori has turned himself into a competent catcher, veteran Ginjiro Sumitani, a two-time Golden Glove winner, is not overworked and has made large defensive contributions. Overall, the Lions are better than average at turning batted balls into outs, and through Friday's games were Japan's best at converting ground balls into double plays.

Tsuji, however, put credit for whatever defense his club can muster on his second-year shortstop Genda.

"Our defense isn't that good," Tsuji said. "That's all on Genda. And the only thing I deserve credit for is writing his name in the lineup."

On Saturday Genda recorded his 510th assist of the season, breaking Japan's 70-year-old shortstop assist record of 502.

With Genda as an ace in the hole between second and third behind them, ace pitcher Yusei Kikuchi, 25-year-old right-hander Shinsaburo Tawata and 32-year-old journeyman lefty Daiki Enokida, who was acquired in a March 16 trade, combined through Friday for a 39-13 record with a 3.49 ERA.

Through June, the Lions bullpen posted a 5.10 ERA and allowed 1.62 walks and hits per inning. But after closer Tatsushi Masuda lost four games in an eight-game stretch, the Lions began looking for alternatives.

After 16 games in middle relief, mid-season acquisition Deunte Heath began to be used in the tightest spots. After going 8-11 in June with one tie, the Lions ended the month only winning-percentage points ahead of the second-place Nippon Ham Fighters.

Since July, when right-hander Kyle Martin was signed and lefty Ryuya Ogawa was purchased from the Central League's Chunichi Dragons, the Lions' bullpen has allowed 1.37 walks and hits per inning and a 4.29 ERA -- not great but not a disaster either.