Ko, starting the day at three-over after a bogey and double bogey in round one, showed her characteristic even temperament to improve to even par and avoid the cut.
Her three-under 68 saw her make four birdies and just one bogey to leap her 45 places up the board and into a tie for 52nd, 10 shots behind leader Yealimi Noh.
Xu is currently two-under for the day and three-under for the tournament in a tie for 25th place.
At the Waste Management Phoenix Open, Ryan Fox also climbed the leaderboard with his five-under 66 moving him up 58 places and into a tie for 24th at four-under, eight shots back from leader Thomas Detry.
Starting round two at one-over, remaining bogey free will have pleased the world No 93 and he heads into the weekend with a chance to earn a top-20 finish or better in his second tournament of the season.
At the Qatar Masters, the Kiwi representation of Dan Hillier and Kazuma Kobori find themselves at different ends of the leaderboard.
Hillier’s two-under 70 was enough to sit him at three-under for the tournament in a tie for 27th heading into the weekend, while Kobori’s one-under 71 got him back to even par but not enough to make the cut.
Will Toogood is an online sports editor and golf reporter for the NZ Herald. He enjoys watching people chase a ball around on a grass surface so much he decided to make a living out of it.