(Sports Network) - Right-hander Brandon Webb tries for a second straight shutout of the Washington Nationals tonight when the Arizona Diamondbacks visit them for game one of a three-game series at Nationals Park.

Webb, who opened the season with nine straight victories, earned win No. 10 against Washington on May 31 in Phoenix, while scattering six hits over nine innings, walking none and striking out eight.

He's 2-2 in six starts since, including a 6-2 win at Florida on June 28.

Webb, whose 12 wins are tied with Angels lefty Joe Saunders, who will also be in action tonight, for the major league lead, is 3-2 in seven career games against the Nationals - six starts - allowing 42 hits and 16 runs in 46 innings.

Southpaw Odalis Perez looks for his first 2008 home triumph for Washington.

The 31-year-old is winless over seven tough-luck starts in D.C. this season, going 0-2 with a 2.27 earned run average in 35 2/3 innings.

He allowed three hits over four scoreless innings at Nationals Park in his last appearance on June 27, getting a no-decision in Washington's 4-2 defeat of Baltimore.

Perez is 5-5 in 20 lifetime games - 18 starts - against Arizona, posting a 3.45 ERA in 104 1/3 innings.

On Sunday in Arizona, Randy Johnson snapped a six-start losing streak with 6 1/3 vintage innings, as the Diamondbacks hung on for a 3-2 win to avoid a three-game sweep at the hands of the San Diego Padres.

Johnson (5-7) struck out 10 and allowed one run on a leadoff homer, one of just three hits surrendered for the veteran lefty, who had not won since tossing six shutout innings against the Detroit Tigers on May 18.

Justin Upton and Mark Reynolds both hit solo homers for Arizona, which had lost four of five.

In Cincinnati, Adam Dunn hit a three-run homer and Edinson Volquez was effective over six innings as the Reds held on to edge the Nationals, 6-5, sweeping a four-game series at Great American Ball Park.

Cristian Guzman drove in two runs, while Felipe Lopez went 2-for-4 with two runs scored for Washington, which has dropped five in a row and seven of its last nine. Guzman will represent the Nationals in the mid-summer classic and now has a 14-game hitting streak.

Collin Balester (1-1) suffered the loss in only his second career start. The right-hander was touched for five runs on four hits. He fanned three and issued three walks.

Arizona has won two of three from the Nationals this season and is 9-2 in its last 11 meetings with them, including wins in its last four games as the visitors.