* Spaniard posts nine-under halfway score
* First-round leader Johnson falls five back
* Defending champion McIlroy misses cut (Updates to end of round)
Sept 2 (Reuters) - Big-hitting Jon Rahm jump-started his day with an eagle and catapulted into a two-stroke lead after the second round at the Dell Technologies Championship in Massachusetts on Saturday.
Rahm sank his eagle putt from 12 feet at the par-five 18th, his ninth hole, and then added five birdies on his inward half for a five-under-par 66 at TPC Boston in Norton.
“It felt like very different, that front nine and back nine,” the Spaniard told reporters after posting a nine-under 133 halfway total in the second of the PGA Tour’s four FedExCup playoff events.
“I played a nearly perfect back nine. Felt like I didn’t miss a shot. Once that (eagle) happened on 18 I felt everything clicked and I just started flushing everything.”
Englishman Paul Casey and Canadian Adam Hadwin shot 65 to jump into a share of second place on seven-under with Americans Kevin Streelman (65) and Kyle Stanley (68).
World number one Dustin Johnson, the first round leader, backtracked with a 72 that included two double-bogeys, falling five shots off the pace. Johnson leads the FedExCup standings after winning last week’s Northern Trust tournament.
Former world number one Rory McIlroy’s disappointing season continued as he shot 74 for four-over and missed the cut in a tournament where he was defending champion. The Northern Irishman has get to win this year.
Another former world number one, Adam Scott, also bowed out early at four-over after the long trip from his native Australia earlier in the week.
Scott made a late decision to play following the birth of his second child. He can head back home now, because he will not be among the 70 players to advance to the penultimate event in the playoff series, the BMW Championship at Conway Farms in Lake Forest, Illinois in two weeks.
Rahm will have no such problems advancing. He is fifth in the FedExCup standings in his first full professional season that includes one win on either side of the Atlantic but mediocre performances in the four majors.
He did not make an auspicious start on Saturday, and a double-bogey at his seventh hole, where he took four shots to hole out from just off the green, left him two-over for the day.
But the eagle steadied the ship, and it was smooth sailing thereafter as he stormed home in 31 strokes. (Reporting by Andrew Both in Cary, North Carolina, editing by Gene Cherry)