2001 Seattle Mariners: 15
Despite losing Randy Johnson, Ken Griffey Jr. and Alex Rodriguez within a 2 1/2-year span, the 2001 Mariners had no shortage of star power thanks to mainstay designated hitter Edgar Martinez, slugging second baseman Bret Boone and Japanese newcomer Ichiro Suzuki, their rightfielder. Seattle was already off to an amazing 32-12 start when it outlasted the Twins for a 5-4, come-from-behind win on May 23 in Minnesota. Martinez homered that day, the first of four he'd hit while batting .438/.517/.812 during the streak. The juggernaut offense scored at least seven runs 10 times in the 15-game span, with Boone homering six times and Suzuki collecting 23 of the league-high 242 he'd wind up with en route to AL Rookie of the Year and MVP honors, not to mention a batting title.
By the time the Mariners finally lost on June 9, they were well on their way to matching the 1906 Cubs' longstanding record of 116 wins and setting a new mark for the Expansion Era. Alas, Seattle fell to the Yankees in a six-game ALCS and hasn't been back to the playoffs since.