Colt from the blue as Knost leads Heritage Open after second round

By SPORTSMAIL REPORTER

Published: 20:54 EST, 13 April 2012 | Updated: 03:13 EST, 14 April 2012

Colt Knost was the halfway leader after shooting a five-under-par 66 on the second day of the RBC Heritage in South Carolina.

While Knost on nine under held a two-shot lead over Carl Petterson, Luke Donald made the cut at two over with a two-under round of 69 as he looks to retain his world No 1 slot.

The Englishman needs to finish in the top eight at Harbour Town to remain ahead of Ryder Cup team-mate Rory McIlroy in the standings.

Surprise lead: Knost is nine under par

He struggled to a four-over-par 75 in the first round but improved second time out with three birdies in a bogey-free first seven holes.

He finally dropped a shot at 15 though, leaving him six shots off the top-eight finish he needs.

Under pressure: Luke Donald

Knost started the day in a three-way tie for the lead with Chad Campbell and Vaughn Taylor.

The American made an ideal start with birdies at the first two holes before finishing a bogey-free round with five birdies overall.

Petterson hit three consecutive birdies, and seven in total, as he followed up yesterday's 70 with a 65 although it could have been even better if he had not bogeyed the 15th.

Boo Weekley and Harris English were a further shot back after rounds of 66 and 68 respectively while Campbell (70) had slipped to a tie for fifth with Robert Garrigus (66).

Taylor hit four bogeys in his 73 to slip to a tie for 16th.

Defending champion Brandt Snedeker hit a 67 today to sit four under in a tie for seventh, with England's Gary Christian one stroke back following his 68.