The Chicago Cubs will look to bolster their shrinking National League wild-card lead against an Arizona Diamondbacks team striving to remain in the playoff race when the teams open a three-game series in Phoenix on Monday night.

The Cubs will turn to newcomer Kevin Gausman (6-11, 4.58 ERA) to try to turn things around after a 10-game stretch that has seen their lead for the NL's top wild-card spot dwindle from 6 1/2 games to two.

The Cubs (75-56) are 4-6 over the past 10 games after salvaging the final game of a three-game set in Seattle with a 19-2 rout on Sunday that included MVP candidate Pete Crow-Armstrong's 33rd home run and 32nd stolen base of the season.

"That's a good finishing game for a series," said Cubs reliever Aaron Civale, who threw four scoreless innings of one-hit ball for the win. "Continue to ride that momentum into the next series."

With a 9-1 run over the past 10 games, the Philadelphia Phillies moved into the second NL wild-card spot, just two games behind the Cubs. The Phillies (73-58) and Cubs have an edge over the San Diego Padres (71-60) and Diamondbacks (69-62) as the four fight for the league's three wild-card spots.

Arizona veteran right-hander Merrill Kelly (8-11, 5.37 ERA) will look to halt a personal two-game losing streak on Monday.

The 35-year-old Gausman, meanwhile, will make his fourth start for the Cubs since being obtained from the Toronto Blue Jays this month. He won his first Cubs' appearance on Aug. 7, throwing seven innings in a quality start in a 6-4 victory at Kansas City, but he has struggled since.

Gausman dealt with cramping of his left thumb last Tuesday against the Chicago White Sox in his most recent outing. The Cubs won 4-3, but Gausman came out of the game in the fifth inning and didn't figure into the decision.

"I just felt like I couldn't keep going," he said after the game. "I kind of couldn't grab my glove without it locking up on me. It's pretty frustrating, to be honest. First start here (Wrigley Field) as a Cub. Obviously not what I'm trying to do."

Gausman is 1-1 with a 6.19 ERA in his first three Cubs' starts, with 16 strikeouts and four walks in 16 innings. The Nationals got to him for six runs in 4 2/3 innings of a 7-0 Cubs loss at Washington on Aug. 13.

Gausman is 7-2 with a 3.20 ERA in 11 appearances (10 starts) against Arizona.

Kelly knows all about cramping, with leg cramps having forced him out of a half-dozen games in the last four seasons. He has struggled since being removed in the sixth inning of Arizona's 4-3 victory over the Los Angeles Dodgers on Aug. 7 because of a right leg cramp.

Kelly is 0-3 with one no-decision in four August starts. He has given up 18 runs on 23 hits, including four home runs, in 19 2/3 innings this month and has an 8.24 ERA.

Kelly is 3-2 with a 4.07 ERA in nine career starts against the Cubs. He was the losing pitcher in an 8-4 Chicago victory on May 3 after allowing six runs on eight hits and three walks in 4 1/3 innings.

But the Diamondbacks are looking forward to September.

"I think we can be really good (down the final stretch)," veteran infielder Nolan Arenado said. "There's still some things we can be better at. Our pitching and our bullpen has been phenomenal. Our defense is phenomenal.

"It sounds crazy, but I still feel like we haven't clicked together as a group as often as we'd like."