Rock and Wood are one stroke ahead of former Augusta State golfer Scott Jamieson, of Scotland; Rafael Cabrera-Bello, of Spain; and Thorbjorn Olesen, of Denmark.
Local teenage standout Matteo Manassero and fellow Italian Francesco Molinari, the 2006 winner, were among seven players three shots back.
Rock and Wood are seeking their first European Tour titles at the Royal Park Roveri club.
Jamie Elson, another former Jaguar, opened with 70.
LPGA TOUR: In Springfield, Ill., Mindy Kim shot a career-low 8-under 64 to take a two-stroke lead after the first round of the LPGA State Farm Classic.
Sarah Kemp and Jiyai Shin are tied for second at 6-under at Panther Creek Country Club. Brittany Lincicome, last week's winner at the ShopRite Classic, birdied the final hole to finish at 67 and is tied for fourth with Yani Tseng and Juli Inkster.
Kim's round featured birdies on Nos. 2, 3, 4, 5 and 6 before a bogey on the par-4 ninth for 32 on the front nine. She matched it on the back nine with birdies on 11, 12, 14 and 17.
I did not expect this at all," she said. "I hit the ball great today. I hit everything close. I think that's what made (the round)."
NATIONWIDE TOUR: In Raleigh, N.C., Kyle Reifers shot 6-under 65 to forge a three-way tie for the lead after the first round of The Rex Hospital Open at TPC Wakefield Plantation.
Reifers, who attended college in North Carolina at Wake Forest, shares the top spot with Matthew Richardson and Justin Peters.
Aiken native Matt Hendrix shot 68 to lead the local contingent. North Augusta's Scott Brown had 69. Former Augusta State golfer Major Manning opened with 71.