Every five or 10 minutes while the game was on hold, Carlos Martinez went to the indoor batting cage to stay loose.
The only concession the St. Louis Cardinals made to a lengthy rain delay was perhaps shortening the right-hander's outing by one inning.
"Carlos was great, he stayed focused," manager Mike Matheny said. "He was conscientious about staying in there and keeping his arm ready and it showed. He was ready."
The 23-year-old Martinez was stingy before and after the break, and the Cardinals hit a season-high six doubles to sweep the Chicago Cubs with a 4-1 victory Sunday night that extended their winning streak to six games.
"He's just looking untouchable," said rookie Xavier Scruggs, who had an RBI single for his ninth hit in five games. "He always had the fastball in the minors when I was playing with him, but now he's got a whole arsenal that's just disgusting."
Jason Heyward, Yadier Molina and Matt Carpenter each had run-scoring doubles for St. Louis, which is a major league-best 51-24 with a nine-game cushion in the NL Central. The Cardinals' 29-7 home record also is tops in the majors and is the second-best start in franchise history, trailing only a 31-4 start by the 1885 Browns according to STATS.
Their home start is the best in the divisional era since 1969, topping the Expos' 28-7 record in 1979.
The Cubs have lost a season-worst five in a row. They were outscored 14-4 in the series, going 2 for 27 with runners in scoring position, and are just 12-32 the last four seasons in St. Louis.
"We've seen Dodger pitching, we've seen Cardinal pitching -- that's really good pitching," manager Joe Maddon said. "And you have a young, inexperienced group offensively, and they're being schooled right now a little bit."
Martinez (9-3) allowed one run and two hits in six innings with six strikeouts. The 23-year-old right-hander worked two scoreless innings before a rain delay of 1 hour and 43 minutes, stumbled a bit in the third when Dexter Fowler doubled and eventually scored on Anthony Rizzo's sacrifice fly, but allowed only a walk after that.
"Even when it's raining and they stopped the game, I kept the focus," Martinez said through an interpreter. "I kept ready for when the game started again."
Martinez and Michael Wacha (10-3) are the first teammates 23 or younger with nine or more wins in the first 75 games since Dwight Gooden and Sid Fernandez had 10 apiece for the Mets in 1986.
Jason Hammel (5-3) struck out seven, but struggled after the rain delay, giving up four runs and six hits in four innings. Hammel worked 7 2/3 scoreless innings against the Dodgers his last time out.
"Honestly, I didn't feel any different," Hammel said. "The difference was, I was dotting before and just couldn't get the ball at the knees after that.
"I think it was either a strikeout or a double tonight.
Trevor Rosenthal earned his 23rd save in 24 chances in a game that was also delayed 46 minutes before the first pitch.
Heyward made an outstanding sliding catch in foul territory down the right-field line on Kris Bryant's pop-up in the first.
Cardinals: LHP Jaime Garcia is likely to make his next start Thursday against the White Sox, getting two extra days to recover from a groin cramp sustained running the bases. OF Matt Holliday could begin running early this week.
The Cardinals are 5-0 on Sunday night.
Cubs: Kyle Hendricks (2-4, 4.46) faces the Mets on Tuesday in New York. He has worked five innings in each of his last four starts.
Cardinals: Lance Lynn (5-4, 2.84), who faces the White Sox on Tuesday, worked six scoreless innings his first outing off the disabled list from a forearm strain.
Link to box score: St. Louis (51-24) 4, Chicago Cubs (39-35) 1