Jordan Spieth seized control of the Charles Schwab Challenge after claiming a one-shot lead at the half-way stage of the tournament, while Phil Mickelson failed to qualify for the weekend.

Former world number one and three-time major champion Spieth earned the outright lead thanks to a four-under-par 66 in Fort Worth, Texas on Friday.

Spieth entered the second round tied with 2017 Masters winners Sergio Garcia atop the standings by two strokes at Colonial Country Club.

Winner of the 2016 Charles Schwab Challenge, Spieth followed up his flawless 63 with another bogey-free round to move clear of the field after play was temporarily suspended due to inclement weather.

Spieth – who is the only bogey-free player through 36 holes at 11 under – holds his 13th second-round lead/co-lead on the PGA Tour – he is six-for-12 to date converting to victory.

Fellow American Jason Kokrak is second following his five-under-par 65, while Garcia (69), Sebastian Munoz (65) and Patton Kizzire (65) are two shots further back at eight under.

Defending champion Collin Morikawa is six shots off the pace after posting a second-round 66.

Justin Thomas (66) registered his 51st bogey-free round of his career. The 14-time PGA Tour champion, who is two under, recorded his 102nd round of 66 or better since 2012 – marking the fourth best on Tour.

Meanwhile, US PGA Championship winner Mickelson missed the cut, despite a heroic 69.

Mickelson, who made history at last week's PGA Championship after the 50-year-old became the oldest major winner in golf history, ended the event two over – just a shot outside the cut line.