Boston Red Sox starting pitcher Rick Porcello delivers during the first inning against the Oakland Athletics at Fenway Park on Tuesday, April 30, 2019, in Boston. (AP Photo/Charles Krupa)

BOSTON — Rick Porcello pitched eight shutout innings and struck out a season-high eight as the Boston Red Sox beat the Oakland Athletics 5-1 on Tuesday night.

Porcello (2-3) allowed only two hits and walked two while winning his second straight start. He also became the first starter to go past the seventh inning for the World Series champion Red Sox in a rough opening month of the season.

Mookie Betts and Mitch Moreland homered for Boston and the Red Sox won for the fourth time in six games.

Tyler Thornburg pitched the ninth and lost the shutout when Robbie Grossman hit a leadoff homer.

Aaron Brooks (2-3) pitched 4 1-3 innings for Oakland, allowing five runs on six hits and three walks.

Betts put Boston up 1-0 with a homer in the first, his sixth of the season. Sandy Leon added an RBI single in the second and Moreland added a two-run homer in the fourth to make it 4-0.

Brooks, who pitched six scoreless innings and struck out six against the Red Sox on April 1 in Oakland, had just two strikeouts this time. He left the game after Rafael Devers doubled in J.D. Martinez, who reached on an error by center fielder Ramon Laureano, to put Boston up 5-0.

Before Grossman’s homer off Thornburg, Oakland’s only hits were Laureano’s leadoff single in the third and a two-out double by Nick Hundley in the fifth.

GOOD BETTS

Betts scored his 500th career run when he touched the plate on his home run. The only other Red Sox players to score 500 runs within their first 700 games were Nomar Garciaparra, Johnny Pesky and Ted Williams.

TRAINER’S ROOM

Athletics: INF Matt Olson (right hand surgery) will join Triple-A Las Vegas to start a rehab assignment Wednesday.

Red Sox: Utility player Brock Holt has been shut down after aggravating a sore shoulder during a rehab assignment with Triple-A Pawtucket. Holt has been on the injured list with a scratched cornea since April 6.

UP NEXT

Athletics: RHP Mike Fiers (2-2, 7.03 ERA) is scheduled to start in the series finale Wednesday afternoon.

Red Sox: Manager Alex Cora said the Boston was still to be determined.