Other than Stan Wawrinka, the only two to have won major titles outside the big four in eons. (Photo of Cilic: Juergen Hasenkopf/REX; DelPotro: David Lobel/INFevents.com)

NEW YORK – How fitting is it that Marin Cilic and Juan Martin del Potro now will be inextricably linked in U.S. Open history?

Worlds apart: Tandil, Argentina and Medjugorje, Bosnia-Herzegovina. (www.distancefromto.net) More

The two longtime friends, so often compared, have much in common.

We'll start with their height: both are listed at 6-foot-6, although their weights are listed on the ATP Tour website at 214 pounds (del Potro) and ... 180 pounds (Cilic). Probably time for an update.

They were both just five days apart, on opposite sides of the world. Del Potro hails from Tandil, Argentina while Cilic was born in Medjugorje, Bosnia – 7,362 miles apart, as the crow flies.

View photos INDIAN WELLS – Juan Martin del Potro enlisted the help of his friend Marin Cilic to test out his ailing wrist in doubles. Del Potro hasn't played since. (Stephanie Myles/opencourt.ca) More

They played in the final of the 14-and-under division at the Orange Bowl tournament in Miami in December, 2002.

Can you believe it? The two had just turned 14. Cilic was the No. 1 seed; del Potro was No. 12. Cilic clearly already had his growth spurt, while del Potro was still a pipsqueak in comparison. But the pipsqueak won, 6-2, 7-6.

Del Potro had the cleaner, more compact strokes of the two – and was much more demonstrative, especially compared to the stoic player he is today. The funniest part of this is that the two kids have to share a bench on changeovers – which kind of means pretending that the person who is sitting a foot away from you doesn't exist for 90 seconds at a time. Imagine if the pros had to do that.

On Jan. 2, 2006, Cilic became the No. 1 junior in the world – two weeks after he ended his junior career at the Yucatan Cup in Mexico. Del Potro's junior high was No. 3 on Jan. 17, 2005; he ended his junior career at the French Open five months later. Both turned pro in 2005.

Incredibly, they never met at the ITF junior level (which are 18-and-under events) during the 2 1/2 years they played at that level. And they never once met in the Futures or Challengers as they made their way up the ladder.

The first time they squared off as pros was at the 2009 Australian Open, where del Potro defeated Cilic in four sets. The second time they met was in the quarter-finals of the 2009 U.S. Open where, again, del Potro won in four sets on his way to his first (and so far, only) Grand Slam title.

The Argentine leads their head-to-head 8-2. They have only played at the biggest tournaments: four times in Grand Slams, once in the quarter-finals of the Davis Cup, and the other five times at the Masters 1000 level. That U.S. Open quarter-final was the latest they've ever met in a tournament, something that's likely to change if del Potro returns to full health after his second wrist surgery and reclaims his rightful spot in the rankings.

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