Federer vs Nadal, the Wimbledon final, 2008. What a match. It was one of those very rare occasions when you could reach for the box of superlatives and tip out the lot, without exaggerating. The tenacity, the skill, the power of both men was - well, reach into that box and pick out whatever you want. If you like tennis and have not seen the match, sell your house, your liver, your grandmother, if you have to. You must watch it.
I watch very little tennis, so I can't compare it to other classic matches, but it was possibly the greatest sporting contest I've ever seen. How often do you get the top two teams or individuals in a sport clash in an encounter that's consistently entertaining, immensely skilled and so nailbitingly close?
A few contenders spring to mind:
In football, there was some cracking games in this year's Champion's League and Euro 2008, but - tense as the Chelsea-Manchester United final was - not between between the best teams in the world. The only match I can think of that might compare to Federer-Nadal was the thriller between Holland and Brazil in the quarter-finals of USA '94.
In cricket, I sadly didn't see the famous 2005 Ashes Series and only caught the very end of the tied 1999 World Cup semi-final between South Africa and Australia. While I've seen a few riveting Black Caps matches, not when they could be considered a truly great cricketing team. That heartbreaking 1992 World Cup semi-final loss to Pakistan might have been up there, had it been a shade closer.
Rugby league had the ever enthralling State of Origin - the Graham Lowe-coached and Wally Lewis-led Queensland team's victory in 1991 sticks in my mind most strongly.
And rugby? Two Wallabies-All Blacks games: the 'Gregan tackle' match of 1994, and the match in 2000 won by a last-minute Jonah Lomu try.
What about you? What are the greatest sporting contests you've seen?