Cape Town - He might cynically be described as a "127 to one" outsider in view of the fact that burgeoning South African, 22-year-old tennis prospect Lloyd Harris could have been drawn against any of the other 127 qualifiers in the men's singles instead of legendary, eight-times Wimbledon champion Roger Federer.

But what is surely a momentous and in the circumstances out-of-the-blue clash against a player who has an awesome record 20 Grand Slam singles titles to his credit - and no one but the most audacious of punters gives Harris any chance of winning Tuesday's game - also stands out as a prime landmark and revealing encounter in the lanky, young South African No 2's career.

What Harris himself has described as "probably the biggest game of my life" - with certainly the biggest crowd in attendance - is designed to provide a signpost as to where his tennis future is heading.

Can Harris ultimately with growing experience scale the heights of a world top 20 player and become a genuine challenger for Grand Slam titles - or remain in the regions of the mid-80 rankings, although no mean feat in itself, where he is presently situated.

His mettle in this awe-inspiring test against Federer will provide a pointer of one sort or another. A crushing, humbling defeat against the 37-year-old Federer could suggest technical and temperamental limitations in his make-up that might halt his progress indefinitely.

On the other hand, putting up a creditable performance against the perennial maestro could act as an encouraging confidence-booster for further progress.

And while rising almost 200 positions in the world rankings in the past two years, Harris has already beaten a player of the calibre of the unpredictable Gael Monfils.

His powerful service alone has the potential to provide Federer with some headaches.

But expecting the biggest Wimbledon upset since iconic, seven-times champion Pete Sampras crashed out to a 143rd-ranked player in the second round in 2002, simply seems a bridge too far even to contemplate.