Owned by Stonestreet Stable and Hal McCormick, Rachel tracked Queen Martha for most of the race under extremely hot conditions. The post-time temperature at Monmouth Park was 95 degrees.
Ridden by her regular jockey, Calvin Borel, the four-year-old filly drew even with the pacesetter on the turn for home and then quickly went past the rival.
Rachel, making her second career start at the Jersey shore track, took command at the head of the stretch and easily notched her second victory of the year. Queen Martha was second followed by Ask the Moon, Stage Trick, Hark, Yes She's a Lady and Fabulous Babe.
The champion stopped the timer at 1:49.78 on a fast track.
Rachel, trained by Steve Asmussen, has won 13 of 18 career starts for $3,446,730. This year she has won two of four races for $498,376.
"She's bigger than she was last year," said assistant trainer Scott Blasi. "She's put on weight. Last year, if you looked at her neck, it was narrow. Now it's filled out. She's just doing great."
Last year in Monmouth's Haskell Invitational, the filly defeated three-year- old males by six-lengths. She was perfect in eight starts in 2009.
In her most recent start this year she won the Fleur de Lis by 10 1/2-lengths on June 12. She came up short in her initial two starts of 2010. She was second to Zardana at the Fair Grounds in the New Orleans Ladies Classic and runner-up to Unrivaled Belle at Churchill Downs in the La Troienne.
Sent off as the 1-10 favorite, Rachel Alexandra returned $2.20, $2.10 and $2.10. Queen Martha paid $2.80 and $2.40, and Ask The Moon paid $3.80 to show.
At Saratoga Race Course, odds-on favorite Devil May Care came from just off the pace to capture the $250,000 Coaching Club American Oaks for three-year- old fillies. Ridden by John Velazquez, the 7-10 favorite covered the 1 1/8- miles in 1:49.42 on a fast surface.
Trained by Todd Pletcher, Devil May Care used an outside move around the final turn to take the lead at the top of the stretch and go on to win her second straight race by four-lengths. Biofuel was second followed by Acting Happy, Bahama Bound, Seeking the Title and Absinthe Minded.
Connie and Michael and Lisa's Booby Trap were both scratched from the Oaks.
Devil May Care, owned by Glencrest Farm, added $150,000 to her bankroll which now stands at $699,000. The filly was coming off a win in the Mother Goose Stakes at Belmont Park four weeks ago. She has won five of her eight career starts. She has a chance to sweep the Triple Tiara series by winning the Alabama Stakes in August.
Devil May Care paid $3.40, $2.40 and $2.10. Biofuel returned $4.00 and $2.60, and Acting Happy paid $2.50 to show.