Angel Cabrera and Carl Pettersson finished on seven-under par 65 on Thursday, heading the leaderboard as thunderstorms stopped play at the US PGA Tour’s Houston Open.

Only 51 players completed their rounds before the inclement weather brought play to a halt at Redstone, the first such delay for the event since 2009.

Defending champion Phil Mickelson, Fred Couples and South African Ernie Els – who needs a victory to qualify for next week’s Masters – had yet to make the turn when play was suspended.

The first round will resume on Friday morning, with officials hopeful of getting the event back on schedule by Saturday.

Ricky Barnes and Jeff Maggert both completed rounds of 66 to lie one off the pace. Brian Harman was at six-under on the course, with three holes to play.

Australians Marc Leishman and Nathan Green are two under par after managing to finish their rounds.