The 52-minute "double-bagel" was the first for the Serb at the elite ATP level, bettering his 6-1, 6-0 win over Argentina's David Nalbandian in the Queen's Club semi-finals in 2008, a rout which took four minutes less.

Djokovic also defeated Britain's Andy Murray by the same scoreline in Miami two years ago.

"I've never had one ("double bagel") before. It's really tough to analyse the match," said the world number four.

"I played enough to win, I had great service games and on his serve I never felt pressure. He didn't put up much of an effort. Anytime you win like this the opponent has to be playing really poorly.

"I know the crowd wanted him to win the last game, but I felt the need to win every game. There's no room for sympathy, we are professionals."

Second seed Djokovic saved three break points in the first set before stepping on the gas against a 59h-ranked opponent who had claimed his first victory since the U.S. Open in the first round here.

Hernych's cause was not helped by committing 40 errors in the loss.

Djokovic improved to 68-18 on the season and now faces Swiss sixth seed Stanislas Wawrinka who defeated Finn Jarkko Nieminen in three sets.

"I'll try to go all the way. Since the Cincinnati final (against Roger Federer) I've been playing really well. I'm getting better and better," added Djokovic, the winner of last month's Beijing title.

Evgeny Korolev will line up against Roger Federer in the last eight after defeating Jeremy Chardy 6-4, 7-6 (7/1), a day after the Frenchman fired 24 aces to humble James Blake.

Meanwhile, compatriot and good friend Marco Chiudinelli kept national hopes high as he beat qualifying compatriot Michael Lammer 2-6, 6-3, 6-3, firing eight aces and breaking three times.

The result marks the second quarter-final in six weeks for the Swiss after a similar performance in Bangkok.

Chiudinelli improved to 9-11 this season and will face France's Richard Gasquet.

Croatia fourth seed Marin Cilic maintained his pace in his chase for one of two places open in the season-ending ATP finals, taking out Serb Victor Troicki 7-6 (9/7), 6-7 (8/10), 7-6 (8/6) in three hours.