PITTSBURGH -- Jason Hammel did not pitch very long but he was able to keep his record perfect.

Hammel lasted just one batter into the sixth inning but raised his record to 4-0, and Anthony Rizzo hit a pair of doubles as the Chicago Cubs beat the Pittsburgh Pirates 7-2 on Monday night.

Hammel's ERA rose to 1.24 after entering the game with a National League-leading 0.75 mark as he gave up two runs with three strikeouts and one walk. His streak of five straight starts of allowing one run or fewer ended.

The right-hander admitted he wasn't at his best.

"With the way things kind of played out, I didn't have my best command," Hammel said. "They extended some at-bats and had some pitches to hit and just missed them. I'd like to be able to throw more than 90 pitches but the ultimate goal is to win. That's all the really matters."

Rizzo hit an RBI double and scored in the third inning as the Cubs went ahead 2-1. He doubled again during a four-run fifth that pushed the lead to 6-1.

The Cubs improved to 18-6, tops in the major leagues, and avoided losing consecutive games for the first time this season while winning for the fifth time in six games.

Dexter Fowler had two hits for the Cubs, including a double, and two stolen bases, and Javier Baez also had two of Chicago's 11 hits. David Ross hit a two-run single in the fifth, Ben Zobrist had two RBIs and Kris Bryant extended his hitting streak to eight games.

"The running theme for us this season has been having good at-bats and we had a lot of them," Ross said.

Gerrit Cole (2-3) was roughed up for six runs -- five earned -- and six hits in 4 2/3 innings after winning his previous two starts. He struck out six but walked four in losing to the Cubs for just the second time in nine regular-season decisions.

As with Hammel, command was an issue for Cole.

"For me, establishing all four corners of the strike zone is key and I didn't do that," Cole said. "I was out of synch all night. I just didn't have it."

Jordy Mercer went 3-for-3 with a walk for Pittsburgh and has reached base in 14 straight games, but Josh Harrison's 10-game hitting streak ended as he went 0-for-4. Andrew McCutchen drove in both Pirates' run with a first-inning home, his sixth, and a ground out in the fifth.

The Pirates (15-11) lost their second straight game after winning six in a row.

The Cubs pulled in front 2-1 in the third inning when Rizzo hit a two-out RBI double and scored on Zobrist's single.

In addition to Ross' single, Zobrist hit a sacrifice fly in the fifth and Matt Szczur scored on a throwing error by Harrison, the second baseman, on the back end of a delayed double steal attempt.

Szczur was removed from the game in the middle of the fifth with tightness in his right hamstring.

Zobrist scored on a wild pitch by Kyle Lobstein in the seventh to increase the Cubs' lead to 7-2.

Home plate umpire Laz Diaz warned both benches after Lobstein hit Zobrist with a pitch to lead off the inning. That came after Hammel hit the last batter he faced, Starling Marte, to start the bottom of the sixth.

There were no further incidents.

The teams had a benches-clearing incident in last year's NL wild-card game when Pirates reliever Tony Watson plunked Jake Arrieta, who went on to a pitch a five-hit shutout.

Cubs manager Joe Maddon and Pirates catcher Francisco Cervelli got into a shouting match after Zobrist was hit. The pair became friends in the offseason when Cervelli worked out in a gym in Tampa, Fla., owned by Maddon's wife, Jaye.

"I like him. I really do," Maddon said of Cervelli. "It's always fun to vent. We've all been there. You have to vent on occasion. The worst thing for your health in the long term is to hold that stuff in. I was directing my comments to the pitcher."

Cervelli said he was just standing up for Lobstein.

"He's one of my guys," Cervelli said. "I've got to protect my guys if someone starts yelling at them."

NOTES: Cubs RF Jason Heyward (sore right wrist) was not in the lineup for the first time this season, and he many also miss Tuesday night's game. He said he has felt pain in the wrist since the first weekend of the season while hitting off a tee. ... Pirates rookie C Elias Diaz will undergo elbow surgery sometime this week. The team's medical staff is confident his ulnar collateral ligament is not torn, which would mean he will likely have an arthroscopic procedure rather than Tommy John ligament transplant surgery. ... The three-game series continues Tuesday night with Cubs RHP Jake Arrieta (5-0, 1.00 ERA) facing Pirates LHP Jon Niese (3-0, 5.08 ERA).