Wall scored 19 points and Washington held the Suns to 33.7 percent shooting en route to an 88-79 victory Wednesday night, its first victory in the Valley since December 2006.
"That's what we pride ourselves on," Wall said. "Any night, anyone can lead us in scoring. We're that versatile. Defensively, that's what we take our pride in. When we play defense, we feel we can beat anybody."
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The Suns took a 26-25 lead after the first quarter on 50 percent shooting. But from that point forward, they made only 17 more field goals on 61 attempts (27.9 percent).
"The second quarter we turned the switch from a defensive standpoint," Wizards coach Randy Wittman said. "Through those last three quarters, that was more what we're accustomed to seeing from this group."
Nene had 17 points and eight rebounds, Kevin Seraphin added 16 points and Trevor Ariza scored 14 for the Wizards, who won for the fourth time in five games. Washington improved to 6-26 away from home, tying Charlotte, Philadelphia and Sacramento for the fewest road victories in the NBA.
The Wizards played without center Emeka Okafor, who missed his first game this season with an illness. Washington snapped a five-game losing streak in Phoenix and swept the Suns for the first time since 2001-02.
Wesley Johnson and Goran Dragic scored 18 points apiece and Luis Scola added 11 off the bench for the Suns, who have lost five of six.
"I wasn't happy with [any] of our young guys," Suns coach Lindsey Hunter said. "It wasn't about mistakes they made. It was about effort. It was about fight, having a sense of urgency. This is unacceptable."
Washington's Bradley Beal left the game with 9:53 remaining with a sprained left ankle.
Phoenix, already without center Marcin Gortat, saw backup center Jermaine O'Neal leave the game with 1:05 left with a strained left calf. O'Neal was helped to the locker room by a pair of teammates after the game.
The Wizards, led by Seraphin's six points, opened the second quarter with a 17-4 run -- including a 15-0 spurt -- to take a 42-28 lead with 4:53 left in the first half.
Washington stretched its lead to as many as 18 before settling for a 59-45 halftime advantage.
The Suns cut the Wizards' lead to nine points by the end of the third quarter and pulled to 75-72 when Hamed Haddadi pulled down an offensive rebound and threw the ball on a straight line into the net with 8:38 remaining.
Seraphin answered with a 15-foot jumper and Wall added a pull-up 15-footer of his own to put the Wizards ahead 79-72 with 7:44 to play.
"When I saw the shot, I knew it was in the range and I took it," Seraphin said. "I didn't really think about it. I just took it."
Washington led by no fewer than five the rest of the way.
"I think the effort wasn't there," Johnson said.
Beal was whistled for a technical foul on the same play on which he was injured. ... Earlier this season, Milwaukee snapped a 24-game losing streak in Phoenix. ... The Suns failed to reach the 100-point mark against Washington for the first time since March 21, 2003, a 19-game span. ... Washington also was without A.J. Price, who missed his fifth consecutive game with a sore right groin. ... Suns G Jared Dudley had been questionable 30 minutes before the game with flulike systems but came off the bench to play eight scoreless minutes. ... Suns G Shannon Brown, who had played eight minutes since the All-Star break, entered with 2:34 left in the third quarter and hit his first shot from the field. Brown had been a DNP in 13 of Phoenix's past 14 games.