As the rest of the pack fought for supremacy in Kuala Lumpur, Campillo and Fratelli were able to post bogey-free rounds of 66 to reach 15 under par.
Scotland's Marc Warren lies tied for fifth with five other players on 13 under after carding 69. His group is also made up of Thailand's Prayad Marksaeng and Phachara Khongwatmai, Japanese pair Hideto Tanihara and Ryo Ishikawa and Italian Nino Bertasio.
England's Lee Westwood had been in contention after the second round -- more than two decades after his first victory at the Saujana Golf & Country Club -- but dropped down the order after a third-round 70.
He finished the third day as part of an eight-man group tied for 11th on 12 under which also included Spain's Pablo Larrazabal.