CHICAGO -- Jake Arrieta admitted he created more drama than he needed but also managed to work out his troubles on Friday.

The Chicago Cubs right-hander became the National League's first 11-game winner as he allowed just two hits and walked three over six innings in a 6-0 victory over the Pittsburgh Pirates.

Arrieta walked the bases loaded with one out in his sixth inning of what was then still a 2-0 game. He struck out David Freese and Matt Joyce to get out of trouble.

"He's so able to step back, take a deep breath and recalculate what's going on," Cubs manager Joe Maddon said. "Some guys get to that moment and they become unraveled. ... But Jake made the pitches he had to, pure and simple."

Arrieta (11-1) matched Chicago White Sox left-hander Chris Sale for most major-league wins after striking out 11.

The Cubs (45-20) are off to their best start since going 45-19 to begin the 1918 season. The Pirates (33-34) suffered their eighth loss in nine games and fell under .500 for the first time this season.

Matt Szczur clubbed a two-run homer in the first inning while Cubs rookie Albert Almora Jr. went 3-for-4 with a walk and two RBI.

Pirates left-hander Francisco Liriano (4-7) suffered his fourth straight loss and sixth in seven starts.

"He pitches himself into some tight spots and the pitch count elevated," Pirates manager Clint Hurdle said. "You see some good things (from Liriano) and then we fall into some traps where the command is a problem for us."

The Cubs scored twice with none out in the first as Dexter Fowler reached on an infield single and Szczur sent Liriano's first pitch to the left-field bleachers for his third home run of the season.

Arrieta said he appreciated the quick lead.

"You like where you're at, that's for sure," Arrieta said. "It just reiterates the aggressive mindset that's needed to accomplish the goal. Whether it's a tie game, we're down a run or were a head, the mindset stays the same of being aggressive in the strike zone and making them swing the bats."

After the first inning, there were numerous threats but no more scoring until the sixth.

The Pirates had runners on first and third with none out in the third, but Arrieta escaped by striking out the next three batters.

Chicago had bases loaded in the fourth inning following Javier Baez's leadoff double and two-out walks to Arrieta and Fowler. But Szczur grounded to short to end the inning.

The Cubs loaded the bases again with two out in the fifth but again came up empty as Miguel Montero lined to right for a third out.

The Pirates, in turn, had the bases loaded with one out in the sixth with three walks as Arrieta topped 100 pitches. But he struck out Freese swinging on a full count and caught Joyce looking on a 3-2 count.

Arrieta was pulled for pinch hitter Chris Coghlan in the bottom of the sixth as the Cubs added three more runs.

Coghlan hustled for a two-base hit, reached third on a wild pitch and scored on Ben Zobrist's single to shallow center with two out.

That marked the end for Liriano, who allowed four runs on six hits in 5 2/3 innings. He walked five and struck out six.

Reliever Cory Luebke walked Rizzo and gave up a run-scoring double to Almora to drive in Zobrist. Luebke went on to load the bases and walked Addison Russell to bring home Rizzo for a 5-0 lead.

The Cubs added a single run in the seventh as Almora's RBI single scored Fowler.

Four Pirates pitchers combined for 11 walks, a nagging issue the Hurdle says must be addressed.

"It's not something we're comfortable with, 10 today, one intentional, that challenges everything," Hurdle said. "We're aware, we're working on things, we're trying to get better. We're not getting better as quickly as we need to."

NOTES: The Pirates didn't reach their Chicago hotel until around 2 a.m. CT Friday but Hurdle maintained his players had plenty of rest for their 1:20 p.m. game. "We got appropriate sleep, we're ready to go," he said. ... Hurdle still needs two victories reach 1,000 all-time as a manager. ... The Pirates briefly returned to playing Central Division teams with this weekend series against the Cubs. Since May 15, Pittsburgh has played 27 of 30 games outside the division and will have 13 straight through July 3. ... The Cubs called up rookie C Willson Contreras from Triple-A Iowa and designated C Tim Federowicz for assignment. Contreras was batting .350 with nine home runs and 43 RBI in 54 games at Iowa. ... Two left-handers earn Saturday starts as the Pirates' Jonathon Niese (6-3, 4.60 ERA) faces the Cubs' Jon Lester (8-3, 1.89 ERA), the reigning NL pitcher of the week.