Kolkata Knight Riders mentor Gautam Gambhir has justified his franchise bidding for Mitchell Starc for a record-breaking amount, saying that the Australia quick will be the X-factor and the leader of the bowling pack. KKR shelled out a jaw-dropping Rs 24.75 crore to get the services of Starc in the IPL auction in Dubai on Tuesday. "He (Starc) is an X-factor, there is no doubt about that. Someone who can bowl with the new ball, bowl in the death overs and more importantly, someone who can lead the attack," Gambhir, who was present at the auction, said.