Roddick angrily threw his racquets towards his entourage after being broken in game seven of the opening set and never gained a foothold in the match as Gabashvili booked his place in the fourth round of a Grand Slam for the first time.
The signs were ominous for the former US Open champion, who has never moved past the fourth round at Roland Garros, when he cracked a racquet by flinging it to the ground at 0-40 3-3 in the opening set.
Gabashvili broke with a delightful drop shot on the next point and when Roddick returned to his chair he furiously pulled out his selection of racquets, hurled them towards his coaching team and barked string tension instructions at them.
The puzzled ball girl picked up the racquets and handed them to Roddick's party, and the American would then never settle throughout a match played in cool, overcast conditions on Court Suzanne Lenglen.
Gabashvili always looked the most likely winner in the lengthier exchanges with single breaks enough for him to surge into a two set-lead over Roddick who engaged in irritable exchanges with the umpire throughout.
Gabashvili, who is still to lose a set here this week, battered Roddick with 58 winners and comfortably returned the American's big serve despite his 72 per cent first service rate.
The world number 114 then broke Roddick twice for a 4-0 lead in the third and held on with ease, sealing victory in an hour and 54 minutes with another forehand winner.
Gabashvili now faces Austria's
The Spaniard, a finalist in Rome earlier in the claycourt season, never got to grips with the Austrian's pace from the back of the court and was two sets down in barely an hour.
Melzer reached the fourth round for the first time in eight attempts when Ferrer crunched a forehand into the net to lose the third set tiebreak 7-1 after an hour and 56 minutes.
Hewitt, who must be sick of the sight of the Mallorcan in Paris after now losing to him in four of the last seven years, rocked the Spaniard by breaking in the opening game, but Nadal hit back immediately and gradually cranked up the pressure.
Hewitt stood toe-to-toe with Nadal in some spellbinding baseline rallies, at one point prompting a forehand winner from the Spaniard which saw him roll over on his back into the red Parisian clay after executing the shot.
The end came after two hours and 28 minutes when Hewitt pelted a backhand long.
Nadal, a four-times champion, next plays Brazilian 24th seed
World number three
In a seesaw performance, the Serbian pumped his fists and smashed his racket onto the ground as he struggled to break Hanescu's resilience on Centre Court.
He came back from a break down, however, in the fourth set to win six games in a row, wrapping up the win when the 31st-seeded Hanescu misfired a service return after two hours and 38 minutes.
Next in line for Djokovic is American
There were 15 Spanish men in the main singles draw on the surface they love more than any other, yet only three remain and two of them -
Verdasco, the seventh seed, went to the brink against Germany's
Almagro, the 19th seed, eased past Ukraine's