(Sports Network) - The National League's hottest team during the month of May invades San Francisco's AT&T Park for the opener of a four-game series, as the Houston Astros attempt to keep up their torrid stretch in tonight's matchup with the Giants.

Houston has gone 8-1 so far in May and began its current 10-game road trip in excellent fashion, taking all three meetings with the Los Angeles Dodgers over the weekend. The Astros completed the sweep with Sunday's 8-5 victory that was fueled by a six-run eruption in the eighth inning.

Trailing 3-1 heading into the game-changing frame, the Astros strung together five consecutive singles off Dodgers reliever Jonathan Broxton to move ahead by a run. Brad Ausmus later delivered a two-RBI single that gave Houston a 6-3 advantage.

Hunter Pence finished 3-for-4 with two RBI for the Astros and Miguel Tejada collected a pair of hits along with two runs scored.

Geoff Geary (1-1) earned the win with a scoreless inning in relief of Shawn Chacon, who held the Dodgers to two runs on seven hits over six frames. Jose Valverde only had to record one out for his eighth save.

The Giants also had a successful weekend, with the club winning its final two tests of a three-game home series with Philadelphia. In Sunday's rubber match, Steve Holm's first major league home run lifted San Francisco to a 4-3 comeback victory.

Holm followed a Randy Winn single with a two-run blast off J.C. Romero in the bottom of the seventh inning to erase a 3-2 deficit for the Giants, who had lost five straight games prior to Saturday's 8-2 decision over the Phillies.

Jack Taschner (2-0) picked up the win after holding Philadelphia scoreless in the top of the seventh, while Brian Wilson preserved the lead in the ninth to notch his 11th save. The San Francisco bullpen combined to toss 4 2/3 shutout frames after starter Jonathan Sanchez was removed in the fifth.

Barry Zito takes aim at an elusive first victory of the season when he takes the mound for the Giants in tonight's opener. The disappointing left-hander fell to 0-7 this past Wednesday in Pittsburgh, although Zito did pitch reasonably well in his team's 3-1 setback.

The former American League Cy Young winner worked five innings against the Pirates and yielded just two runs on five hits. Zito was making his first start since April 27, having been briefly removed from the rotation due to his struggles.

The quirky veteran won his only career start against Houston with seven innings of one-run ball at AT&T Park on May 23 of last season.

Zito will be opposed tonight by Astros ace Roy Oswalt, who appears to have rebounded from a slow start of his own.

Oswalt lost his first three starts of 2008 and pitched to a 9.00 earned run average over those games. Since then, the hard-throwing righty has gone 3-0 with a 3.55 ERA during a stretch of five outings.

The three-time All-Star struck out a season-best nine batters against Washington on Wednesday, although he wound up with a no decision after surrendering three runs over seven innings.

Oswalt is just 2-5 with a 4.07 ERA in 10 career starts against San Francisco and has not fared well pitching at AT&T Park, where the 30-year-old has compiled a 1-5 record and a 5.30 ERA in seven mound trips.

The Giants won four of their six encounters with Houston last season and have gone 9-3 against the Astros since 2006. San Francisco has taken five of the six matchups held at AT&T Park during that two-year stretch.