OZONE PARK, N.Y. – Gemologist took the lead at the top of the stretch and turned back a late challenge from Alpha to win Saturday afternoon’s Grade 1, $1 million Resorts World Casino New York City Wood Memorial at Aqueduct Racetrack by a hard-fought neck. Now 5-for-5, the bay son of Tiznow will bring his perfect record and $702,855 in graded stakes earnings to Churchill Downs as one of the likely favorites for the May 5 Kentucky Derby.

“That’s a great win, he’s a great horse,” said a beaming Elliott Walden of WinStar Farm, winning owner of Gemologist. “This stamps him as a Derby prospect, which we’re excited about. We needed the earnings [$600,000] today.”

The field for the Kentucky Derby is limited to 20 3-year-olds, based on graded stakes earnings.

Gemologist, who was sent off as the 6-5 favorite by the Wood Memorial day crowd of 12,514, stayed close to the pace and off the rail as My Adonis tracked The Lumber Guy through opening fractions of 23.04, 47.57 and 1:12.54. Asked for run by jockey Javier Castellano on the far turn, Gemologist charged three-wide into the lead as the field straightened for home, and had enough left to fend off the hard-charging Alpha.

Gemologist, who returned $4.40 for a $2 win bet, covered the 1 1/8 miles in 1:50.96.

“I had a great trip,” said Castellano. “Turning for home, he was looking around at horses. When I asked him, he took off again. I like that. I was concerned [when I saw Alpha closing] because my horse was still looking around at the crowd. When he saw the horse coming, he took off again.”

A winner of all three of his 2011 races – including the Grade 2 Kentucky Jockey Cup at Churchill Downs – Gemologist heads into the Derby with one other start this year, having captured a one-mile allowance race at Gulfstream Park on March 16 by seven lengths. His neck victory Saturday was the narrowest winning margin of his five races, having won his four previous starts by a combined 15 ¾ lengths.

“So far, it would be hard to be unhappy with anything he’s done so far his whole career,” said trainer Todd Pletcher, who took the 2010 Wood with Eskendereya and who one month later won the Derby with WinStar’s Super Saver. “It was great to see. It looked like he had a little something left after the wire, so I think from a conditioning standpoint, with a good mile race and a good 1 1/8-mile race under our belt, hopefully we can have a good month of training leading up to [the Derby].”

Joining Gemologist in Louisville on the first Saturday in May will be Alpha, who suffered his first loss of 2012 after being pinched back on the first turn. The winner of Aqueduct’s Grade 3 Withers and the Count Fleet, Alpha earned $200,000 for finishing second in the Wood and has now amassed $380,000 in graded stakes earnings.

“He was very good in the gate, he got checked into the first turn hard, but he still ran great with a little traffic and took the dirt well,” said Kiaran McLaughlin, who trains Alpha for Godolphin Stable. “We got beat a ‘zop,’ but we’re going on to May 5. It was a good race and a good test, he did everything right except not win”

Teeth of the Dog, the longest shot on the board at 53-1, finished three lengths back in third, and was followed by Tiger Walk, The Lumber Guy, Street Life, and My Adonis. Casual Trick was pulled up by jockey Corey Nakatani midway through the race after suffering breathing problems, which he has battled all year.

“He’s sound, he’s fine,” said Casual Trick’s Hall of Fame trainer, Nick Zito, who saddled Jackson Bend to victory in the next race, the Grade 1 Carter Handicap. “He’s perfect, other than he can’t breathe.”