Nick Kyrgios has continued his stellar form to defeat big-serving American John Isner in straight sets and put Australia on the brink of the Davis Cup’s final four.

A red-hot Kyrgios won 7-5 7-6 (7-5) 7-6 (7-5) at Brisbane’s Pat Rafter Arena to give Australia a commanding 2-0 lead in the World Group quarter-final tie.

After Jordan Thompson’s shock win over Jack Sock in the opening rubber, it leaves them just one win away from a semi-final date against Italy or Belgium in September.