Before each day's play in Flushing Meadows, we'll preview and predict three must-see matches.

If you go by the rankings, this looks like a mismatch. Cecchinato, a 22-year-old Italian, is No. 102, while Fish, who has played only sporadically over the last two years, is No. 574 at the moment. Of course, this is about more than numbers. Whatever the result, the 33-year-old American says the Open will be his last tournament. In his comeback from an anxiety disorder, he's already managed to bring that topic to the forefront among fans and fellow players, and thus added some outside-the-lines import to his career that it wouldn't otherwise have had. On Monday, he'll begin his last stand in front of what's sure to a packed Grandstand audience. Winner: Fish

This one may be of interest primarily to fans in the U.S., but it could have a bearing on the tournament as a whole—the winner might end up facing Serena Williams in the third round. Sloane (age: 22, rank: 29) and CoCo (age: 23, rank: 43) have had their ebbs and flows in recent years, but each is capable of pulling off a big upset and making a deep run at a major, and each will want to show off their best in New York. Vandeweghe leads the head to head 2-1, and has won both of their meetings on hard courts, but Stephens came out ahead most recently, in Strasbourg this spring. Winner: Stephens

The first day's main event will go off last in Ashe, when Nadal, a two-time Open winner, takes on one of the ATP's rising stars. Coric isn't just the tour's teen of the moment, he's one of the very few players who can boast of a winning record against Rafa. Granted, they've played just once, last fall in Basel, and Nadal was preparing to have his appendix removed, but Coric did close Rafa out in straight sets. Nadal's results haven't improved a whole lot since, but he remains upbeat, and he hasn't lost a match at the Open since 2011. Coric will be ready for nights like this soon, but he has struggled with stamina at the majors so far this year, and that's not something you want to struggle with against Rafa over three out of five sets. Winner: Nadal