Andy Murray hopes Washington’s August temperatures prepare him for the U.S. Open. (Julian Finney/Getty Images)

The match was nearly nine years ago, but Andy Murray can still recall the searing heat of that August afternoon in Washington.

“I remember like 4 o’clock, that was the earliest the match started, it was absolutely brutal,” Murray said of his win over Paraguay’s Ramon Delgado at the 2006 Legg Mason Tennis Classic, where he was the eventual runner-up. “Brutal conditions [and] very, very tough to play.”

Murray, a two-time Grand Slam winner, will return to Washington this year to play at the Citi Open starting Aug. 1, tournament officials announced Thursday. The world No. 4 hopes the heat and humidity will help prepare him for a deep run at the U.S. Open held three weeks later. Fifth-ranked Kei Nishikori also has committed to play in the annual tennis tournament at Rock Creek Park Tennis Center.

“Andy and Kei are two of the most dynamic and popular athletes in world, so we’re thrilled that they have committed in this year’s Citi Open,” tournament director Jeff Newman said. “We know the D.C. fans will come out strong to support them.”

The two would be the highest-ranked pair of singles players to participate in the tournament since world No. 1 Andre Agassi and sixth-ranked Andy Roddick played in 2003. Murray would be the first player ranked above No. 5 in the world to play in the tournament since then.

“The last couple of years I haven’t done so well in the buildup to the U.S. Open,” Murray said in a telephone interview Tuesday. “I felt it would be good to try something different. I played Washington a few years ago. The conditions were obviously very challenging, tough conditions, but it felt good to play matches in that sort of heat in the buildup to the U.S. Open.”

Murray, winner of the 2012 U.S. Open and 2013 Wimbledon, will also use the trip to visit Under Armour headquarters in Baltimore. The 27-year-old Scot signed a four-year deal with the apparel giant in December after spending most of his career with Adidas.

Nishikori, 25, will be playing in Washington for the third consecutive season and fifth time overall. He lost in quarterfinals to Richard Gasquet of France last year, a career-best result in Washington.

“I always enjoy playing on the center court [in Washington],” he said in a telephone interview Tuesday from Indian Wells, Calif., where he was preparing for the BNP Paribas Open. “The weather is tough, but it’s a great time to have good matches before the U.S. Open.”

The Japan native made history in September at Flushing Meadows as the first Asian-born male to reach a Grand Slam final and followed up his career year with a win at Memphis last month — his eighth ATP title.

Donald Dell co-founded the event in 1969 and has seen the local tennis tournament evolve through various iterations. Along with a new title sponsor and stadium upgrades, the tournament became a shared event between the ATP and WTA in 2012. And in 2009, the men’s event became an ATP World Tour 500 series tournament, which included an increase in points and prize money with the aim to attract more high-profile tennis players, Dell said.

“There’s a lot of positive locker room talk, and it’s helped us attract some of the best players in the world,” Newman said. “We want people to obviously point at our week on the calendar and say, ‘That’s a must-see event and a must-play event.’ ”