Playing for the Royal Challengers Bangalore (RCB) in his club's opening game of the 2018 Indian Premier League, McCullum smashed a thunderous 43 from 27 balls to get his side away to a brisk start.
Coming up against his fellow Heat 'Bash Brother' in Chris Lynn's Kolkata Knight Riders, McCullum's RCB put on 176 from their 20 overs.
It didn't proved to be enough however as Kolkata chased the total down in 18.5 overs, with Lynn contributing 5 in his first game since injuring his shoulder in Australia's T20I Tri-Series Final against New Zealand.
By passing the major milestone, McCullum joined West Indies batsman Chris Gayle as the only two players to have scored 9,000 runs in the T20 format.
McCullum was the Heat's leading run-scorer in the 2017-18 KFC Big Bash League season with 248 at a strike rate of 135.