Texas, March 28 -- Northern Ireland's Rory McIlroy blamed a "pedestrian" start as he finished five shots off the lead after the first round of the Houston Open here.

The world number two carded an opening-round 70, hitting two birdies and two bogeys at the Memorial Park course to leave him five strokes off early joint-leaders Keith Mitchell, Taylor Pendrith, Alejandro Tosti and Ryan Gerard, the BBC reported.

McIlroy, who is hoping to complete a career Grand Slam by winning the Masters next month, opted to play in Houston for the first time since 2014 in preparation for Augusta.

"A little pedestrian I guess is a good way to describe it," McIlroy said.

"Made a few par saves early on that I needed to and then had quite a few chances on t...