Mathias Gronberg took advantage of sloppy rounds from the leaders to catapult himself into a share of the lead in the Children's Miracle Network Classic.

The Swede carded a round of six-under-par 66 to move level with overnight leader Justin Leonard, as well as Justin Rose and George McNeill, who had begun the day tied for second.

Gronberg began his round slowly, with only one birdie on the opening nine, but three on the first four holes coming back set him on course for the top.

Leonard could only manage a round of 71, one under par, as three bogeys marred his card, while Rose signed for a round of 69 after struggling on the first half of the course.

McNeill likewise hit a 69 to leave all four tied on -13 under going into tomorrow's decisive round.

Australian Nick O'Hern and Swede Carl Pettersson are one shot further back on 12 under after rounds of 66 and 67 respectively today.