The 43-year-old American, contesting the Wimbledon singles for a record 24th time, still retains the easy power that once made her the queen of Centre Court but succumbed 6-4 6-3 after a nasty early fall hindered her movement.
Williams, whose last Wimbledon title was in 2008 against sister Serena, won the opening two games but looked in serious trouble in the next as her bandaged right knee buckled under her while she moved to intercept a volley.
The Centre Court crowd winced as she crumpled to the turf, but after staggering back to her chair and receiving treatment the old warrior spirit kicked in and she battled on.
The 28-year-old Svitolina, who at least was born when Venus first appeared at Wimbledon, unlike 53 players in the women's draw, won four games in a row and took the opening set despite a fierce struggle to hold serve at 5-4.
Williams, who also won the title in 2000, 2001, 2005 and 2007, went down swinging, unleashing some thunderous strokes to claw back two games and hint at a fightback.
Svitolina got the job done though and as the evening sunshine turned to shade, Williams walked off beaten, waving what might have been a final farewell to the crowd.
Later, Teenage starlet Coco Gauff was knocked out of the first round with an opening day defeat to Sofia Kenin that was more missed opportunity than shock result.
That the American was drawn against resurgent compatriot Sofia Kenin already represented a major hurdle -- Kenin's current ranking of 128 belies her status as a recent former grand slam champion, and the 6-4 4-6 6-2 loss, although hard to swallow for seventh-seed Gauff, was no surprise upset.
Forget that Kenin had been forced to qualify for the main draw here. Both players have been ranked as high as world number four, before injury and illness took its toll on Kenin, and there was little to choose between the two on a chilly night on Wimbledon's Court One.
In the men’s draw, Norwegian fourth seed Casper Ruud put away France’s Laurent Lokoli 6-1 5-7 6-4 6-3 to reach the second round in four sets.
American Michael Mmoh upset 11th seed Felix Auger-Aliassime of Canada 7-6(4) 6-7(4) 7-6(4) 6-4 in a four-hour clash to claim a surprise win and reach the second round.
Mmoh, who made headlines earlier this year by beating Alexander Zverev to reach the Australian Open third round, is ranked 119 in the world.