With the score locked at 8-8, Buckingham calmly slotted the invaluable two-pointer for his side's first victory since April. Earlier winger Todd Byrne had scored the only try of the first half to give his side a 6-0 lead.
Buckingham converted that try and added the first of his two penalties to stretch the advantage to 8-0 in the 49th minute. But the Sea Eagles came back with a try to New Zealander Jack Afamasaga and a Clint Halden conversion to trail just 6-8 with 22 minutes to play.
Halden was on target with a penalty right in front of the posts to level things up at 8-8 after 69 minutes before Buckingham secured a huge confidence-boosting victory.
Man of the match for the Vodafone Auckland Lions was Aidan Kirk, who played in the centres and not his normal slot at fullback.
Vodafone Auckland Lions 10 (Todd Byrne try; Steve Buckingham conversion, 2 penalties).
Manly Sea Eagles 8 (Jack Afamasaga try; Clint Halden conversion, penalty).
Halftime: 6-0 Vodafone Auckland Lions.