With their 100th victory against 62 losses, they became the most successful regular-season team in franchise history -- eclipsing by one win the previous record set by the 2002 World Series champions, who reached the postseason after winning the American League Wild Card.
The Angels' 100 wins were evenly divided: 50 at home, 50 on the road.
Now, they move on to the AL Division Series against the Red Sox beginning Wednesday at Angel Stadium.
"I think it means a lot to us, setting a franchise record like that, and it was good to do it for our fans," said Saunders, who recovered from a kidney stone-related hiatus to deliver six two-hit, no-walk innings while striking out nine in preparation for his Game 3 start in Boston on Sunday.
"It's also a good way to go into the postseason, with a lift," Saunders added. "You don't want to go in getting swept. It was a great game for us confidence-wise."
Napoli's 20th homer and two doubles accounted for four runs batted in, continuing a torrid September.
"That's special," Napoli said. "Being the first team to win 100 games in franchise history, it's nice.
"This was a good day for us in a lot of ways. We got a win, Joe pitched great after his kidney stone [passing], the bullpen came in with some shutout innings. Most of all, it gives us some momentum going into the playoffs."
The Angels are the first team in the Majors to reach triple figures in wins since the 2005 St. Louis Cardinals won 100 games, and they are the first AL club to do it since the '04 Yankees won 101.
"It's a nice milestone," said Angels manager Mike Scioscia, who had attached priority to making the playoffs and then forging the best record in the AL to assure home-field advantage throughout the postseason. "There are things more important we accomplished, but for as hard as these guys worked -- how they put out since Spring Training -- 100 is a nice round number."
Individually, Francisco Rodriguez, who rested on the final day, smashed the all-time single-season saves record with 62 successes in 69 opportunities. Bobby Thigpen of the 1990 Chicago White Sox held the previous record of 57 saves.
K-Rod obliterated is own previous club record by 15 saves.
By winning the AL West by a club-record 21 games over the Rangers, the Angels are the first team to claim a division crown by at least 20 games since the 1999 Indians.
Since the advent of divisional play in 1969, seven teams have outdistanced their division rivals at 20 games or more. Four of those clubs went on to win the World Series.
The 1975 Big Red Machine from Cincinnati was the first to do it, taking the National League West by 20 games over the second-place Dodgers en route to their World Series triumph over the Red Sox in seven games.
The White Sox of 1983 were the next to do it, claiming the AL Central by 20 games over the runner-up Royals. The Sox were eliminated by the eventual-champion Orioles in four games in the ALCS.
The 1986 Mets steamrolled the NL East, finishing 21 1/2 games ahead of the Phillies. They went on to rock the Astros in six games in the NLCS before stunning the Red Sox in seven in the Fall Classic.
In 1995, two division powerhouses cruised to the finish line. The Braves finished 21 games ahead of the Mets in the NL East, and went on to take their lone World Series title of the Bobby Cox era when they dispatched the Indians in six games. The Tribe had rolled through the AL Central, leaving the second-place Royals 30 games off the pace.
The 1998 Yankees rolled into the postseason after seizing the AL East by 22 games, the Red Sox in futile pursuit, then claimed the World Series in a four-game sweep of the Padres.
The following season, the Indians came home 21 1/2 games ahead of the second-place White Sox, but fell in five games to the Red Sox in the ALDS.
Lyle Spencer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.