Roy Halladay has done that to the Nationals for nine years.The Nationals will try to end their staggering slide to Halladay in order to set a franchise record for their longest winning streak at Philadelphia on Tuesday night.Washington (25-17) has won 12 of 15 meetings with the Phillies (21-22) after taking the opener of this three-game set 2-1 on Monday.The Nationals' success against their NL East rivals includes a 6-1 record at Philadelphia, winning five in a row to match their longest run there last accomplished bridging the 1973 and 1974 seasons.Surpassing that mark will be much more difficult against Halladay (4-3, 3.22 ERA) since Washington's last win against the two-time Cy Young Award winner came as the Montreal Expos on June 28, 2002.Since then, the right-hander is 11-0 with a 2.09 ERA against the Expos/Nationals franchise, including a 6-0 mark in seven starts with the Phillies.Halladay hasn't been nearly that sharp over his last six trips to the mound, going 1/3 with a 4.35 ERA. However, he won his latest outing Thursday despite allowing three runs and two homers in eight innings of an 8-7 victory at Chicago.He may appreciate some improvement from the offense as he tries to keep Philadelphia from a season-high four-game skid.The Phillies have two runs and 13 hits while going 2 for 19 with runners in scoring position their last two games. They're hitting .208 in the past nine meetings with the Nationals."We need some guys to get hot and start hitting the ball for us," manager Charlie Manuel said. "Guys have to pick one another up."Placido Polanco, who had two hits Monday, is doing his part. The third baseman is hitting .366 with four doubles, one homer and four RBIs in the past 12 games, raising his average 36 points to .286.He owns a .377 average in his past 18 meetings with Washington, and is 3 for 8 versus Jordan Zimmermann, Tuesday's scheduled starter.Zimmermann (2-4, 2.58) is looking to beat the Phillies for the first time. The right-hander is 0-3 with a 6.00 ERA while allowing a .318 average and five homers in four starts against them.He struggled against them again May 6, allowing three runs and seven hits with four walks and a hit batter in six innings of a 9-3 home loss. That defeat is part of his 1/3 stretch with a 3.91 ERA.Zimmermann turned in perhaps his worst start of that stretch Thursday, giving up four runs and seven hits, including a career high-tying three homers, with six strikeouts in six innings of a 5-3 loss to Pittsburgh. That came five days after he was impressive in a 2-1 win at Cincinnati, fanning a season-high nine while allowing one run in seven innings.He's 2-1 with a 1.35 ERA in three road starts on the season.Ian Desmond is batting .346 with three homers and eight RBIs in 11 games. The shortstop had two hits with a homer while plating two runs Monday, giving him a .339 average with three home runs and nine RBIs in the last 13 meetings with Philadelphia.