After defeating Rafael Nadal in five sets in the second round of Wimbledon 2012, Lukas Rosol stood adamant about not wanting his career to be remembered for a single victory, regardless of how shocking and special it was.

And, to Rosol’s credit, he has done a respectable job not letting the limelight overwhelm him. Ranked No. 100 in the world at the time of his victory over Nadal, Rosol thrust his ranking all the way up to a career high of No. 33 earlier this season. In addition, the Czech won his first career title in Bucharest.

Unfortunately for Rosol and the other giant killers, competing at a consistently high level on Tour following a career-defining win is often harder than obtaining that career-defining win in the first place.

The first problem for these players is the weight of expectation. For example, consider Sergiy Stakhovsky after he stunned Roger Federer at Wimbledon this year. Stakhovsky’s expectations for the rest of his career and even the rest of the tournament were probably exponentially higher after he had taken out the greatest player of all time at a tournament that he has dominated.

It is illogical to base expectations on a player on the match of his life, a type of match that is almost impossible to reproduce. While higher expectations are not bad, keeping them within the confines of what that player has done in the vast majority of his matches is much more realistic.

Rosol, Stakhovsky, and Steve Darcis, Nadal’s 2013 Wimbledon nemesis,  all failed to win the next match following their triumph. Rosol was bounced in straight sets by Philipp Kohlschreiber, Stakhovsky fell in four sets to Jurgen Melzer, and Darcis withdrew with an injury.

This phenomenon extends well beyond Wimbledon.  In 2011, Stephane Robert of France stormed back from two sets down against Tomas Berdych at Roland Garros to score a massive upset at his home major. In the second round, Robert won only three games against Fabio Fognini, a talented player but clearly below Berdych’s caliber.  And he has left minimal impact on the Tour since then.

On a smaller scale, consider the recent results of Gael Monfils.  Two weeks ago, he ambushed Federer in Shanghai and took a set off Novak Djokovic. Last week in Vienna, Monfils lost to world No. 213 Jaroslav Pospisil in straight sets.

Giant-killers from a relatively obscure nation, like Stakhovsky’s Ukraine, often shoulder less pressure than if they had hailed from traditional tennis powers. Imagine if an American like Jack Sock or Denis Kudla had beaten Roger Federer at Wimbledon this year. Each of their matches would be watched and examined with the utmost scrutiny.

The next issue is associated with what some have called the hangover effect. Similar to what happens after a player wins a tightly contested set over an elite opponent, a monumental upset can create a hangover.

After winning a tight set, all of the tension and excitement is sapped from the environment, and there is usually a lull at the beginning of the next set. Imagine this phenomenon occurring over two days, letting the full extent of emotions and energy drain out over 48 hours.  The giant-killers must combat this deflation of emotions. And their next match is almost always on a smaller, secluded outside court.

In Rosol’s case, for example, no element of the electric, exciting, nerve-filled atmosphere on Wimbledon Centre Court against Nadal could be reconstructed in a third-round match against Philipp Kohlschreiber on Court 12.

Ultimately, the reality for almost all of these guys is that they will fail to realize the goal Lukas Rosol set out for himself. In most cases, they entered in a zone they have never entered before and are not likely to ever enter again. When Lukas Rosol and Steve Darcis retire, they will undoubtedly be remembered almost entirely for defeating Rafael Nadal at Wimbledon.

Eleven years later, George Bastl’s name appears only in references to his second-round victory over Pete Sampras at Wimbledon in 2002. Eleven years from now, the only time that any of today’s giant killers will be mentioned is when referencing their single career-defining victories.