(SportsNetwork.com) - James Shields tries to become the third pitcher in the majors with six wins when the San Diego Padres welcome the Chicago Cubs to town Tuesday for the opener of a three-game series.

Bartolo Colon of the New York Mets and Seattle Mariners ace Felix Hernandez are the only two pitchers with six wins.

Shields is 5-0 with a 3.11 earned run average in eight starts and so far his first season with the Padres has been a success. Shields recorded his third straight victory in last Wednesday's 4-2 road defeat of the Mariners and allowed one run in six innings with nine strikeouts and three walks.

The right-handed Shields had given up five runs in each of his previous two appearances and San Diego is 5-3 when he takes the hill. Shields has pitched at least six innings seven times and is 2-0 in three home starts. He has faced the Cubs twice in his career, going 1-0 with a 4.38 ERA.

Ian Kennedy can be just as dominant as Shields, but wasn't in Sunday's 10-5 loss to the Washington Nationals in the finale of a four-game series. Kennedy was touched for six runs in five innings, struck out six and walked four.

Justin Upton hit a pair of solo home runs in a three-hit effort and Jedd Gyorko also homered for the Padres, who have dropped five of their last seven.

"It's been a grind for us the last couple of weeks," Upton said. "We have to get back to what we did early in the year and that's playing as a team."

The Cubs were aiming for a perfect seven-game homestand until dropping a 3-0 decision to the Pittsburgh Pirates Sunday in the finale of a three-game series at Wrigley Field.

After sweeping the New York Mets in four games and taking the first two meetings with Pittsburgh, Jake Arrieta left the Cubs hanging even though he pitched seven innings of one-run ball, struck out seven and walked one. Arrieta was outdueled by Pirates veteran A.J. Burnett, who tossed seven shutout innings.

"We played well again today," Cubs manager Joe Maddon said. "They pitched well. They beat us on the mound."

Chicago produced five hits and Anthony Rizzo ended 0-for-2 with two walks. Kris Bryant was 1-for-2 for the Cubs, who had won six in a row.

Jason Hammel will draw the start for the Cubs Tuesday and is 3-1 with a 3.11 earned run average in seven appearances. Hammel pitched well in a no-decision versus the New York Mets last Wednesday and delivered eight innings of one-run ball in a 2-1 victory.

Hammel struck out six batters and has fanned at least five six times. The right-hander has plenty of experience against the Padres in his career and is 4-3 with a 5.06 ERA in 14 games (13 starts).

San Diego won two of three games at Wrigley Field in late April.