Pitching will make the difference for the Giants

Good pitching beats good hitting.

It’s as immutable a part of baseball physics as the spin on a curveball or the sink of a fastball.

“Pitching wins championships,” San Francisco Giants outfielder Aaron Rowand said. “It’s cliche. But it’s true.”

Which is why the Giants, who have baseball’s best pitching staff, will play past the end of the regular season Sunday while the Kansas City Royals, the second-best hitting team in the majors, are going to finish last in the American League West.

“Pitching and defense,” said Cody Ross, another Giants outfielder. “That makes teams go forward.”

Over the last five seasons, the team that has led the majors in pitching has advanced into the postseason four times. Over that same span, the team that led the majors in home runs was only half as successful.

Five of the last eight World Series teams finished in the top four in their respective leagues in earned-run average. During that same period, none of the majors’ top-hitting teams made it that far. And one, the 2008 Texas Rangers, didn’t even have a winning record.

“Every championship team that wins the World Series … what do you have to have?” said Padres bench coach Ted Simmons, an eight-time All-Star catcher. “You’ve got to have really good defense. Because all the teams that win do. You have to have strikeout-quality pitching. And the closer is clearly, in almost every case, a strikeout pitcher who can affect the defense.

“So defense, strikeout pitching and a closer. They have all those three things. And not a word — not one word — about hitting.”

That’s because while hitters can affect a game, pitchers can dominate it. Seattle’s Felix Hernandez, who leads the big leagues with a 2.27 ERA, had nearly four times as many strikeouts as earned runs allowed. And he allowed only one baserunner per inning.

“If you’re pitching well, there’s less people on base,” Rowand said. “If there’s less people on base, there’s less chance to score runs. It’s fairly simple.”

This season, no team has been better at keeping things simple than the Giants, who have a 3.38 ERA, the best mark in the majors in seven seasons. They were even better down the stretch, posting a 1.78 ERA in September, the fifth-best mark by any team in any month in the last 90 years.

Included in that was an 18-game span in which no opponent scored more than three runs in a game. No team has done that since the dead-ball era.

Pitching can be a fickle friend, though. Because while it can give you a title, it can also take one away. Or at least delay the celebration.

Needing a victory Saturday to clinch the National League West and their first division title since 2003, the Giants were baffled by the Padres’ Tim Stauffer, who held them to only a hit in 61/3 scoreless innings in a 4-2 win. The victory extended San Diego’s season at least one more day, and that the Padres relied on pitching to get to the brink of the postseason is no surprise.

The Padres, after all, had baseball’s second-best ERA, only one-tenth of a run behind San Francisco. The Padres are also tied for the major league lead with 20 shutouts and their relievers have been even better — the bullpen ERA of 2.81 is the best in baseball in seven seasons.

So while the NL West may not have a dominant power hitter such as Albert Pujols and may lack the glitz and pizzazz of the AL East, pitching has made it arguably the most competitive division in baseball.

“There was a time just a little while back when people were suggesting what a weak division it is,” said Colorado Manager Jim Tracy, whose Rockies were in the thick of the playoff chase until the season’s final week. “It’s not to be considered one of the weaker divisions anymore. It’s pitching rich. You can look up and down every club in the division … and there’s very good pitching”

That cannot only frustrate your opponent, but can give your team a big boost of confidence at the same time.

“When you go out there with our staff and have a chance to win every day, you come to the ballpark as a player, you go ‘OK, who’s starting for us? Hey, we’ve got a pretty good chance to win today,’ ” Rowand said. “That’s very uplifting mentally as a team.”

Rowand has been through it before. In 2005, he played for a Chicago White Sox team that got four consecutive complete games in the AL Championship Series, then won the World Series behind a pitching staff that gave up less than three runs per game in the postseason.

“When you get to the playoffs,” he said, “pitching is at a premium.”

The Giants are in the postseason. And what happens from here on is likely to be decided on the mound. That suits Rowand just fine.

“In a playoff atmosphere,” he said, “I like our chances against anybody with our starting staff.”

kevin.baxter@latimes.com