(SportsNetwork.com) - Jon Lester takes another crack at his first win as a member of the Chicago Cubs on Sunday when they play the rubber match of their three-game series with the San Diego Padres at Wrigley Field.

Lester, who signed a 6-year, $155 million deal with the Cubs this offseason, has struggled in his two starts, posting a 7.84 ERA over 10 1/3 innings. He was hammered by the Cincinnati Reds on Monday for six runs and 10 hits in six innings, but drew more attention for his pickoff throws over to first base.

The left-hander, who hadn't attempted a throw over to first since 2013, threw wildly to first base on an attempt, leading some to speculate that he may have a case of the yips. .

"Obviously I haven't hit my stride yet," said Lester. "But I don't want to use anything as a crutch, by any means. Things have to be better ... I'll get back to being the front end of that chain instead of the back end and letting guys down. It'll be better."

San Diego, meanwhile, will turn to righty Andrew Cashner, who is 0-2 with a 4.09 ERA. Cashner lost to Arizona on Monday, but surrendered four unearned runs in an 8-4 loss. He has struck out 15 batters in 11 innings this season.

Cashner, who started his career with the Cubs, is 0-1 against his former team with a 4.15 ERA in four games (2 starts).

Chicago evened this series at a game apiece on Saturday, as Starlin Castro's walk-off single in the 11th inning lifted the Chicago to a 7-6 win.

With the bases loaded against star closer Craig Kimbrel (0-1) and the defense rearranged with five players in the infield, Castro ripped a single through the left side to score Anthony Rizzo.

After a rough major league debut Friday, Kris Bryant reached base five times, including an RBI single and an infield hit in the 11th.

Miguel Montero also hit a pair of homers and drove in three runs.

The Cubs led 6-2 entering the ninth, but Phil Coke and Hector Rondon each allowed two runs to send the game to extras. Zac Rosscup (1-0) pitched two scoreless innings to keep the Padres off the board after the ninth.

"You never panic," said Montero. That's what a winning team does. ... We never stopped against a good team."

San Diego won four of seven meetings with Chicago last season.