New York Mets pitcher Kodai Senga surrendered a season-worst five runs in five innings of work in a 5-0 loss to the Cincinnati Reds on Thursday.
Senga (4-2) gave up eight hits, five of them in a four-run first inning, while striking out seven and walking one at Great American Ball Park in Cincinnati.
In the first, the 30-year-old right-hander allowed a leadoff double to Jonathan India and retired TJ Friedl and Spencer Steer before the next five batters reached base.
Senga, playing his first year in the major leagues after 11 seasons with the Fukuoka SoftBank Hawks in Japan, regrouped to strike out five in a row in one stretch but wound up with his second loss in three starts.
He also yielded a solo home run to Steer in the fifth inning.
Limiting walks has been one of Senga's main focuses after he walked three or four batters in each of his previous six outings.
"Today I was able to locate my pitches better than usual," Senga said. "Because of that, my pitches went to some hittable zones. I'll try to learn from this and do well next time."
The Reds' Ben Lively (1-0) threw three innings in relief for the win.
At Target Field in Minneapolis, San Diego Padres pitcher Yu Darvish got a no-decision after allowing two runs and striking out seven over six innings in a 5-3 loss to the Minnesota Twins.