CHICAGO -- Boston Celtics coach Brad Stevens typically texted guard Avery Bradley before games during the regular season with a hint of the defensive game plan, a name or two Bradley would be tasked with slowing down. Stevens admits it probably wasn't hard for Bradley to anticipate those assignments: He just had to identify the top scoring threat on the opposing roster.

"I think he can figure out which ones he's guarding; he just looks at the stat sheet and goes from there," said Stevens. "He’s got to expect that he’s going to have to guard not only the wings but also some shooting 4s and some point guards, and we’ll go wherever we need to with him because he’s such a good defender."

Bradley's marching orders for Boston's first-round series against the Chicago Bulls has been pretty obvious: Make things as difficult as possible for Chicago's primary offensive weapons, but especially All-Star swingman Jimmy Butler.

The Bulls as a team are shooting just 38.6 percent (17-of-44) against Bradley through five postseason games. Butler, who shot 45.5 percent during the regular season, is shooting just 37 percent (10-of-27) when Bradley is the primary defender this series, according to ESPN Stats & Information.

In fact, if you zoom in on Boston's three wins since falling into a 2-0 hole, Bradley has held Butler to 6-of-17 shooting (35.3 percent). During Boston's Game 5 win on Friday, Bradley scored a postseason career-high 24 points while limiting Butler to two points on 1-of-5 shooting plus a turnover.

Bradley's defense is a big reason the Celtics can clinch this best-of-seven series during Game 6 in Chicago on Friday (ESPN, 8 p.m. ET).

So what's it like having Bradley checking you on the defensive end?

"Oh, it's tough," said teammate Jae Crowder, who experienced Bradley's defense as an opponent during Crowder's early years with Dallas, and still gets a taste in practices. "You're going to get his best shot. He's going to get into you, make it difficult. He's very good on the perimeter, moving his feet, directing you, making you go where he wants you to go.

"He's a hell of a defender. He makes you work."

Bradley earned first-team All-Defense honors last season (earning the third-highest vote total behind only Draymond Green and Kawhi Leonard) and was the top vote-getter at the guard position for Defensive Player of the Year (sixth overall in that balloting).

An Achilles injury that sidelined Bradley for an extended stretch might conspire against him in this year's award balloting. Bradley appeared in 55 of 82 regular-season games, and despite some memorable moments – such as a mesmerizing late-game defensive stand against Kyrie Irving in March -- his advanced defensive numbers weren't quite as glossy as last season.

This postseason, however, Bradley has been sensational. And he has essentially been locked onto Butler and Dwyane Wade the entire series. A whopping 86.4 percent of plays with Bradley as the primary defender have come with him on Butler or Wade, according to ESPN Stats & Info.

Bradley is allowing a mere 0.72 points per play, according to Synergy Sports data. Among the 114 players with at least 30 possessions defended this postseason, Bradley ranks ninth in points allowed per play. If you focus on the 63 players with at least 50 defensive plays, Bradley escalates to No. 2 behind only Toronto's DeMar DeRozan (0.615 points per play).

What separates Bradley from other quality perimeter defenders?

"First of all, I think Avery has continued to get better," said Stevens. "Then, I think he’s able to use his, not only foot speed, but his conditioning, his athleticism, his ability to get up under guys and just make it as tough as possible. Great offensive players in this league are hard to stop, and you try to make it as hard as you can, and that’s what Avery tries to do.

"And he does it very consistently. That’s the other thing. You have to have a DNA, a makeup about you that wants to do that every night, and he’s got that. Hey, every night is a huge, huge challenge for Avery because he’s guarding the best players in the league, and certainly when you’re talking about Butler and Wade, that’s as good as it gets when you’re talking about wing scorers."

Entering the season, Bradley said his goal was to make the rest of the league respect him as a two-way threat. He averaged a career-high 16.3 points per game on 46.3 percent shooting. His 3-point percentage spiked to 39 percent; his career mark is 36.6 percent.

That Bradley was able to carry the Celtics' offense in the first half of Game 5, while keeping Butler in check for much of the night, speaks to his influence at both ends of the floor.

And that's no easy task, considering the energy expended on both sides of the ball.

"It takes a lot," said Crowder. "But with him knowing that all the guys on the court have his back, he's able to do what he does best, which is pressure the ball. And we just try to help him out as much as possible.

"It takes a lot from a guy like him to guard Jimmy the whole game and make him work. We just want to make [Butler] work as much as possible. I think we've done a great job thus far."