Frittelli and Lombard both shot rounds of 71 while Australia's Nathan Holman, the only other player under par for the tournament, carded a 70 to move to outright fourth place at one-under.
Sweden's David Lingmerth, the overnight leader, dropped back to even par, level with Australia's Matthew Millar, after a round of 75 on a heavily-congested leaderboard with 20 players within six strokes of the lead.
The big-hitting Varner, who recently graduated to the U.S. PGA Tour, climbed 27 places to grab his share of the lead in the event, co-sanctioned by the European Tour and the PGA Tour of Australasia.
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He birdied the third, seventh and eighth holes to move to level par then reeled off three birdies in a row from the 14th despite struggling in the blustery conditions.
"I haven't played in that much wind in a long time," he said.
"When bad things happen, you've just got to shake it off and go onto the next one and today I did that really well."
(Writing by Julian Linden in Singapore; editing by Sudipto Ganguly)
