Courtesy of MCTMaking his sixth straight Memorial start, 2011 Masters champion Charl Schwartzel shot a 65 (7-under) to start the 37th annual Memorial Tournament from Muirfield Village Golf Club in Dublin, Ohio, and finished Thursday at the top of the leaderboard.Schwartzel’s strong outing was followed by Scott Piercy at 6-under par, who has three top-ten finishes on the PGA Tour this year.Four strokes behind Piercy lands Tiger Woods shooting 1-under 71 on the afternoon. The last time Woods shot a 71 in the first round came in 2000, where he went on to win his second of five tournament titles at Muirfield. The winner of the 2012 Memorial champion may have had the strongest pairing of the day, playing alongside the likes of Fred Couples (-2) and Keegan Bradley (-1), respectively.Former world No. 1 Rory McIlroy is threatening to miss the cut for the second straight year. After his first 18 holes, McIlroy wrapped-up round one shooting a 78 (6-over). Despite his back-to-back poor starts, McIlroy has managed leave Muirfield with top ten finishes in 2010 (T-10) and 2011(5th).Perhaps one of the bigger stories from Thursday was the performance of 14-year-old Guan Tianlang of China. Making his name known from making the cut at last April’s Masters, the amateur finished at an even par-72 going into Friday’s round. Tianlang is the youngest player to ever make a cut and the fourth youngest player to make a start on a PGA Tour event.