Zambia boss Avram Grant praised his side following an important Africa Cup of Nations win over the Ivory Coast.
Kennedy Musonda scored the only goal of the game at the Levy Mwanawasa Stadium to secure top spot in Group G and their place in the AFCON finals with one match still to play.
Chipolopolo top the standings with 10 points, one point ahead of the Elephants on nine points.
Sierra Leone on five points, most recently drew 1-1 with bottom side Chad, who have three points from their five games played.
This is the second successive AFCON qualification Grant has secured with a game to spare.
He said on ZamFoot: “After 51 years of coaching, this is the best victory ever,” the former Chelsea manager said.
“Beating the African champions with all the difficulties we faced with our players injured, I am very happy.”
Grant’s side were missing the likes of Patson Daka, Lubambo Musonda and Lameck Banda.
Zambia finish their qualifiers against the Leone Stars on Tuesday.