It is the essence of basketball: One player attempts to score, and a defender attempts to stop him. And with NBA offenses pushing the limits of pace and space in an effort to fire up scoreboards, players who have the ability to impede the ball in a one-on-one setting have more value than ever.

Defending on the ball is a special skill, and something altogether different than just being a quality defender. Draymond Green is the reigning Kia Defensive Player of the Year and is probably the best overall defender in today’s NBA. But that status is due in large part because of his nose for help defense and his versatility, particularly his ability to create and take advantage of mismatches in the post.

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And while Green is certainly a competent on-ball defender out on the wing, it is probably also the best way to attack him if you’re an opposing player with a speed advantage.

So here is our list of the top five on-ball defenders in the NBA right now. If you get the ball iso’d against them on the wing, maybe think twice before you waive off that screen from your teammate. One-on-one, these guys want to play that game tonight.

1. Kawhi Leonard, San Antonio Spurs

He may not be the most excitable fellow in the NBA, but he is one of the most tenacious individual defenders the league has ever seen. At 6-foot-7 with a seven-foot wingspan, Leonard presents an intimidating collage of arms and hands, capable of forming an impenetrable blockage. More than that, there are times Leonard can be downright predatory on defense, attacking the offensive player and snatching away the ball. Out of all the elite on-ball defenders in the NBA, nobody is better than Leonard.

2. Andre Roberson, Oklahoma City Thunder

While Roberson is a below-average offensive player — he shot 24.7 percent from the 3-point line last season — the Thunder forward more than makes up for any offensive liabilities with his defensive prowess. An athletic 6-foot-7 swingman, Roberson is able to guard almost any position, from power forward to shooting guards, and should team with newly acquired Paul George to strengthen what an Oklahoma City defense that ranked 10th last season in defensive rating.

3. Avery Bradley, Detroit Pistons

Bradley had a tough season last year as a member of the Celtics, battling injuries to play in just 55 regular season games. But Bradley’s defense was typically superb, and perhaps even better than the statistics suggest when you consider that he was often in the backcourt alongside Isaiah Thomas, who opposing teams often targeted. Now a member of the Pistons, Bradley, at just 26 years old, should remain a member of the NBA’s elite defenders for years to come.

4. Tony Allen, Free Agent

Allen is the best defensive specialist remaining on the free-agent market, after spending the bulk of his career in Memphis, where he came up with the whole “Grit and Grind” ethos that has defined the Grizzlies. At 35 years old, Allen is the oldest player on this list, but he remains durable (he played in 71 games last season) and an elite defender (he averaged 3.3 deflections per game last season). Allen manages to make playing defense fun to watch.

5. Patrick Beverley, LA Clippers

While this list has mostly focused on wing defenders, Beverley is perhaps the best point guard defender in the NBA. After years of making a name for himself on the defensive end, Beverley made his first All-Defensive first team last season with the Houston Rockets. A pesky 6-foot-1 guard, Beverley lacks the size of some of the other players on our list, but misses nothing when it comes to heart and drive. Beverley employs a physical brand of defense, becoming as much of a psychological deterrent as anything, which has endeared him to fans over the years.

HONORABLE MENTION: Giannis Antetokounmpo, Jimmy Butler, Danny Green, Draymond Green, LeBron James, Chris Paul, Marcus Smart, PJ Tucker, John Wall

Lang Whitaker has covered the NBA since 1998. You can e-mail him here, find his archive hereor follow him on Twitter.

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