The North East Valley combination caused a major upset when they beat Chris Le Lievre (Eastbourne) and Richard Girvan (Onehunga) 22-14 at the New Zealand championships in Dunedin.
The experienced Girvan was the World Bowls fours champion in 2008.
''We were lucky,'' McLean said.
''Two ends went our way early on and it gave us a buffer and the confidence to know that we had a chance.''
Fives on the second and third ends set the scene for the game and North East Valley was up 11-0.
McLean moved the jack back for five on the second end and the five on the third end were all draw shots.
Girvan and Le Lievre rallied and scored seven shots on the next four ends to close the gap to four points. But six shots on four ends extended the buffer to 18-8 after 13 ends and the game was called off when North East Valley scored four on the 16th end.
Another southern giant-killer was the Stirling combination of Jamie Nicol and Bob Sanders which downed Black Jack squad member Blake Signal (Stokes Valley) 18-17.
The Composite pair of Ethan Kelleher and Sean Ingham beat Australian-based Black Jack Ali Forsyth, a former winner of the world champion of champions singles, and Andre Smith (Havelock) 17-8.
McLean and Will reached the semifinals with a 16-13 win over Sanders.
The teenage pair of Elliot Mason (Forbury Park) and Sheldon Bagrie-Howley (Gore) made the Wellington pair of Ben King and Gary Lawson work hard for a 21-17 win.
Heavy rain drowned the greens and stopped the semifinals. They will be played tomorrow afternoon.
When play was stopped, Black Jack Tony Grantham and Australian Michael Nagy were leading King and Lawson 7-6 after eight of the 18 ends.
The other semifinal between Will and McLean and brothers John (Adelaide) and Ross Munro (Forbury Park) was locked at 4-4 after four ends.
''It was the right decision to stop play and come back on Friday afternoon,'' Lawson said.
''You should only go indoors if it is the only option.''
