PITTSBURGH (AP) The Chicago Cubs, who start four rookies most days, haven't been in a pennant race since 2008.
However, instead of being nervous, the young Cubs are enjoying the moment.
Jake Arrieta pitched seven strong innings, Anthony Rizzo tied a career high with four hits and the Cubs beat the Pittsburgh Pirates 5-0 on Tuesday night for their sixth straight win.
''It's just a lot of fun right now,'' said Rizzo, the All-Star first baseman. ''It's been fun to see how this has developed over the last few years to the point where now we're in contention and playing important games.''
Arrieta (12-6) allowed two singles - Andrew McCutchen in the fourth and Starling Marte in the seventh - while striking out five and walking three.
Tommy Hunter and Justin Grimm completed the three-hitter with one inning each as the Cubs (58-47) matched their longest winning streak of the season from May 11-16 and moved 11 games over .500 for the first time since the end of the 2008 season.
In his last nine starts, Arrieta is 6-1 with a 1.38 ERA. He improved to 5-1 in his career against the Pirates.
''You could appreciate his stuff based on horizontal and vertical (measurements) on the scoreboard, how much his ball was moving, and his velocity, at the same time,'' Cubs manager Joe Maddon said. ''He's an interesting pitcher. I will say it again, he's not there yet. He's still learning how to utilize all his weapons. There's another level of Arrieta.''
Rizzo doubled and scored in both the third and fifth innings as he led the Cubs' 14-hit attack with the fourth four-hit game of his career.
Chris Denorfia had three hits while Starlin Castro doubled home Rizzo twice and Jorge Soler drove in the first and last runs with a bases-loaded walk in the first inning off J.A. Happ (4-7) and a single in the sixth.
Chicago drew within three games of the National League wild card-leading Pirates (61-44), who remained 5 1-2 games behind the St. Louis Cardinals in the Central.
Happ had a rocky Pirates' debut, giving up four runs and eight hits in 4 1-3 innings with two walks and six strikeouts. The lefty was acquired in a trade with Seattle last Friday and was 0-1 with a 9.00 ERA in his last four starts with the Mariners.
''I was anxious to get out there,'' Happ said. ''I put us in a tough spot but I'm going to be better and I'm starting to look forward to the next one.''
Marte had two hits.
The Cubs made it 3-0 in the third when Castro hit his first RBI double and scored on a single by David Ross.
Castro greeted reliever Jared Hughes with his second run-scoring double in the fifth.
Cubs: LHP Tsuyoshi Wada (left deltoid inflammation) was activated from the 15-day DL and was optioned to Triple-A Iowa, where he was on a rehab assignment. ... 3B Kris Bryant was hit on the left hand by a pitch in the sixth inning but stayed in the game.
Pirates: RHP Rob Scahill (right forearm tightness) is scheduled to begin a rehab assignment Thursday by pitching two innings for the rookie-level Gulf Coast League Pirates.
Cubs LHP Jon Lester will be brought back on short rest to start Friday against San Francisco. He threw just 31 pitches during a 1 2-3 innings stint Monday night against the Pirates in a game eventually postponed because of rain.
Cubs: RHP Dan Haren (7-7, 3.42 ERA) debuts for his new team Wednesday night in the finale of the rain-shortened two-game series after being acquired from the Miami Marlins last Friday in a trade.
Pirates: LHP Jeff Locke (6-6, 4.21) has a 2.81 ERA in his last nine starts and allowed only one home run in 51 1-3 innings during that span.