Lu gained the first ATP championship match appearance of his 13-year professional career with a 6-4, 7-6 (7-4) decision over Ferrer, who was going for a fifth title in Auckland, having won the Heineken Open in 2007 and then the last three years.
Lu forced Ferrer into 11 break-point situations and finished off three of them, including one in the second set that got him into the tiebreaker that ended the match.
Lu faces third-seeded John Isner in Saturday's semifinals. Isner got by Roberto Bautista Agut 3-6, 7-6 (7-2), 6-4 in his third consecutive three-set match in the tournament.
Isner won 70 percent of the points on serve but still had his serve broken once in each the first and second sets. He lost only three points serving in five games of the third set, however, and converted the only break chance of the set to advance. Isner is 7-9 in previous ATP title match appearances. He lost in his last two title matches.
Isner dropped only three games in his only previous match with Lu.
The Heineken champion's check is worth $82,500, with $43,450 going to the loser of Saturday's final. Ferrer and Bautista Agut took home $23,535 as semifinalists.