Jordan Spieth has been disqualified from the Genesis Invitational after signing an incorrect scorecard. The former world No 1 has taken full responsibility for the mistake after Tiger Woods withdrew from the same tournament due to illness. Spieth had a strong start to the competition at the Riviera Country Club, shooting an opening round 66 to be just two behind leader Patrick Cantlay. His first nine went well on Friday but he then dropped three shots, including a double bogey on the 18th, to go round in 73. Spieth was 10 shots off the lead when he was informed that he had been disqualified fr…