The Angels lead Texas by five games with eight to play, including a four-game set against the Rangers that begins Monday night at Angel Stadium.
Rookie Kevin Jepsen (6-4) was charged with four runs and three hits in the Oakland eighth, including a tying RBI single by Suzuki after the right-hander struck out Rajai Davis and Ryan Sweeney with runners at the corners. Cust's double gave the A's an 11-10 lead, and Daric Barton greeted Matt Palmer with an RBI single before Ellis capped the rally with a three-run homer.
Craig Breslow (8-7) pitched 1 1-3 innings for the victory after giving up an RBI single by pinch-hitter Gary Matthews Jr. that put the Angels ahead 10-9 in the seventh.
Cust was 3 for 5 with four RBIs and Barton was 4 for 5 with two RBIs. Suzuki had three hits and a season-high four RBIs during Oakland's 19-hit outburst, raising his team-high RBI total to 85.
Darren Oliver relieved John Lackey after five innings with a 9-6 lead and gave up two runs in the sixth. Adam Kennedy hit an RBI double and scored on a two-out wild pitch to Sweeney.
Lackey allowed six runs and 10 hits while striking out two. The right-hander, who hadn't allowed a home run in his previous five starts, gave up a two-run shot by Suzuki in the first and a three-run shot by Cust in the fifth.
Suzuki gave the A's 2-0 lead in the first with his 15th homer after a two-out walk to Sweeney. Juan Rivera responded in the bottom half with a three-run shot over both bullpens, giving him new career highs in homers (24) and RBIs (86).
All three runs off Dana Eveland in the Angels' first were unearned after shortstop Cliff Pennington botched a potential double-play grounder by Abreu when he took a throw from second baseman Ellis off the bag and wasn't able to get the out at first, either.
The Angels increased their margin to 9-2 with six runs in the fourth. Jeff Mathis hit an RBI single, and Kendrick scored when Kennedy hit him in the back with his throw to the plate after fielding Maicer Izturis' grounder. Chone Figgins chased Eveland with a two-run single and Abreu hit a two-run homer on Brad Kilby's first pitch, giving him 100 RBIs for the season.
Eveland threw 79 pitches over 3 1-3 innings, allowing eight runs, five hits and four walks.
NOTES: The Angels will announce Jered Weaver as the first winner of the Nick Adenhart award on Monday as the team's pitcher of the year. Adenhart and two friends were killed when an alleged drunken driver broadsided their car at an intersection just hours after he held the Athletics scoreless through six innings on April 8 in a no-decision against Eveland. ... Abreu needs one stolen base to become only the second player in the Angels' 49-year history with at least 100 RBIs and 30 steals in the same season. Bobby Bonds had 115 RBIs and 41 steals in 1977. ... Only 10 times this season has Angels closer Brian Fuentes started the ninth inning and retired the side in order to get a save. The last time was back on Aug. 10. ... Pennington, who ignited Oakland's eighth-inning rally with a leadoff double, has no RBIs in 39 career at-bats against the Angels. ... Abreu and Albert Pujols are the only players to drive in 100 or more runs in each of the last seven seasons. Alex Rodriguez needs seven more in the Yankees' final seven games to join them. ... Any combination of three Oakland losses and Seattle wins will guarantee the A's their seventh last-place finish since division play began in 1969, and their first since 1998. ... Lackey's first-inning strikeout of Davis enabled the Angels' pitching staff to reach the 1,000-strikeout mark for the sixth straight season, the longest streak in club history. ... Davis extended his career-best hitting streak to 14 games with a single in the fifth.