Winning a major is not for the faint of heart. It becomes even more difficult when trying to accomplish something only a rare few have managed to do in the entire history of the sport. No active player knows this better than Serena Williams. The American has already had to overcome some close calls through the first week of the US Open in her attempt to become just the sixth player to complete the calendar-year Grand Slam. She may be called upon to do it once again when she faces Madison Keys in the fourth round.

There is bound to be plenty of interest in this duel. Some of that interest will stem from wanting to see if Williams can keep her quest for the Grand Slam alive. Portions will also come from the fact that it is two Americans doing battle at their home major. But attention will also be paid to Keys, who is quickly becoming one of the rising stars of the WTA and looking more and more like a potential successor to Williams as she tries to usher in a changing of the guard.

One match does not cement a changing of the guard, but Keys unquestionably has the tools necessary to bring it a step closer. She is one of the few players on tour who can match the power of the top seed from both the ground and on serve, and she will not be intimidated at the prospect of trading shots with her countrywoman from the baseline. Williams is superior in the movement department, which gives her an advantage in terms of defense and extending the rallies when she needs to. Keys appears to be the more adept up at the net, however, and she has done a good job of recognizing when to move forward and making the most of it when she does. Given how evenly matched they are in relation to firepower and their respective strengths and weaknesses, this one will ultimately come down to who can seize control of the rallies first.

Gaining the upper hand and being able to capitalize when doing so will be affected by how each of these players manages her nerves. This will make for one of the most intriguing aspects in this second meeting between Williams and Keys. Williams has the experience that comes with winning so many majors and has the security of knowing that she is in the more favorable position to control what is happening on the court. She has won her only other encounter with Keys as well, which occurred in the semifinals of the Australian Open earlier this year. But Keys will not necessarily be lacking in belief either. While she has never been to this stage of the US Open, the fact that she made the final four in Melbourne should help her on this occasion. She also showed a lot of poise in her routine win over Agnieszka Radwanska, a woman she had lost to in their four previous encounters. Furthermore, she can benefit from her coach Lindsay Davenport, a former Grand Slam champion who personally knows what it takes to beat Williams. And finally, Keys should be able to swing a lot more freely as the underdog with not nearly as much on the line as Williams.

All of the ingredients are there to make this a high-quality contest. As usual, it is hard to bet against Williams, who will be the favorite. But this match has to be considered a possible upset special. Keys has the game to take it to Williams, and if she can come up with the goods on the crucial points, she could play spoiler to Williams’ date with history.

Everyone is familiar with the phrase “luck of the draw.” Sometimes it works out for the better and other times for the worse. In the case of Jo-Wilfried Tsonga, his luck at the US Open has been good. He was placed in what began as the most open section of the draw, and it has deteriorated even further with each passing round. He now finds himself as the favorite to emerge as the semifinalist from this section, but he will first have to get by what could turn into a stumbling block in his countryman Benoit Paire.

It would be understandable if fans were not familiar with Paire and overlooked him as an obstacle to Tsonga’s progress in New York. The younger Frenchman has spent a fair amount of time off the tour the last couple of seasons with injuries, and it has only been in recent months that he has been able to showcase the kind of tennis he is capable of producing. Of course, Tsonga is no stranger to injury interruptions either. The 19th seed has been slowed by injuries in 2015 and has struggled to get his game going into full flight as a result. It puts him on a little more equal footing with Paire and leaves the possibility of an upset very much on the table.

It should be entertaining to see how this one shakes out between these two offensive-minded players, who go about their business in different ways. Tsonga is the more explosive of the two and will certainly look to dictate proceedings with his forehand. He is also a little more agile around the court and more of a risk taker. Paire, by contrast, prefers to lean on his backhand as his bread-and-butter shot, and he arguably has a slight advantage on the serve due to being the taller of the pair. That is not to say that handling Tsonga’s serve will be a walk in the park, and both men are apt to earn their fair share of easy points with that stroke. Both also share a willingness to charge the net, and while Tsonga has more versatility in the forecourt, it is the lankier Paire who is tougher to pass.

Effectively utilizing their strengths with consistency over the course of the match will be affected by how each man rises to the occasion, and it is anyone’s guess as to who that will be. The more obvious answer is Tsonga. Although the US Open has somewhat surprisingly been his worst of the four majors, he has still been to the latter rounds of the majors, unlike Paire who is in unfamiliar territory. Tsonga also knows he has beaten Paire in their only two prior matches without the loss of a set. Playing higher-ranked opposition has not seemed to bother Paire this week, however. He kicked off his US Open campaign by upsetting Kei Nishikori and dispatched Tommy Robredo in his previous match. Based on the way he took it to Novak Djokovic in Cincinnati, it is safe to assume that Paire is feeling confident and has the weapons to get the job done against Tsonga if he plays well.

Hopefully both Paire and Tsonga do play at their best, since that would make for some spectacular all-court tennis and enthralling shot-making. If that happens to be the case, the edge has to go to Tsonga as the player with the valuable experience to go along with his game, but no one, especially Tsonga, should ignore Paire’s chances of causing yet another upset.