Twelve-time grand slam winner Djokovic was a late addition to the draw following his third-round exit in Monte Carlo last week, but his stay in Catalunya proved even shorter.

An inspired Klizan performance in the first set put the world number 140 in control and, although Djokovic clinched the second, the 28-year-old settled the match with a single break in the decider.

The result represents a first win for Klizan over Djokovic, who appeared to have accepted his fate late in the third.

Klizan's winning of the first point was met by a roar from a section of the crowd and the Slovakian's fans would have plenty more to celebrate.

The five-time winner on the ATP Tour won that opening game on Djokovic's serve with a fierce forehand down the line and, after surviving a break point to move 3-1 in front, Klizan stretched his lead yet further.

Klizan was giving the former world number one the run-around and a sublime drop shot wrapped up the sixth game, before he clinched the set with an ace.

Djokovic appeared to have settled early in the second set and made a crucial break to go 3-1 up, the Serbian displaying the range of shots his opponent had stunned him with in the opener.

Another break - to love, this time - confirmed Djokovic had found his stride, and one more without conceding a point pulled him level with Klizan.

The underdog battled to an important hold in the opening game of the deciding set but cut a frustrated figure after firing off a wayward shot in the sixth, throwing his racket at the clay in dismay.

His frustration was misplaced, however, as a couple of sloppy Djokovic errors led to a decisive break that allowed Klizan to serve out the match.