Jake Arrieta of the Chicago Cubs is pitching a no-hitter through six innings against the Boston Red Sox at Fenway Park.

Arrieta has allowed only one runner, walking Mike Napoli in the fifth. The right-hander has thrown 90 pitches and struck out seven.

Arrieta took a perfect game into the seventh inning of his last start, on Tuesday at Wrigley Field against Cincinnati, before Billy Hamilton hit a leadoff single.

The Cubs lead Boston 2-0.