That was a close one.

The Boston Red Sox won their series opener against the Chicago White Sox at U.S. Cellular Field on Monday, but the bullpen showed its weakness once again. Boston entered the bottom of the ninth inning with a fairly comfortable 5-2 lead, but Jean Machi came *this* close to losing it after giving up two runs.

But the Red Sox prevailed, thanks in large part to a solid night from Joe Kelly and a big offensive effort from one outfielder.

GAME IN A WORD

RusneyCastillo.

OK, so that’s a name and not one word, but the outfielder still handled this contest at the plate and in the outfield with a nice assist to end the sixth inning.

IT WAS OVER WHEN …

Castillo stepped up to the the plate.

The 28-year-old smacked a three-run home run to dead center to put the Red Sox up 3-1 in the second inning, and he tacked on a couple more in the sixth with a two-run double, just to be safe.

IN THE BATTER’S BOX

— Castillo’s two-run double proved to be the difference-maker, and the outfielder took over the offense from there. He was responsible for all of the Red Sox’s runs, going 3-for-4 to go with five RBIs.

Castillo now has a nine-game hit streak.

— Brock Holt returned to the lineup and went 2-for-3 with a walk, a strikeout, a stolen base and two runs thanks to Castillo (of course).

— Hanley Ramirez scored twice, too, after going 1-for-3 with a hit by pitch.

— Ryan Hanigan also put in some work for Boston, though he only saw home plate while he was catching. He went 2-for-4 with a strikeout.

— Boston didn’t get much production from some of its best hitters, though. David Ortiz and Travis Shaw went hitless, while Mookie Betts and Xander Bogaerts didn’t get a hit until the ninth inning.

ON THE BUMP

— Joe Kelly settled down for the Red Sox after giving up a first-inning solo shot to Jose Abreu. He didn’t allow a hit through 3 2/3 innings after Abreu’s homer and had only one earned run after that.

Kelly finished the night with five hits, four strikeouts, one walk and the two earned runs over 7 1/3 innings and earned his fifth straight win.

— Robbie Ross Jr. came in for Kelly and left quickly after Adam Eaton grounded into a double play to end the inning.

— Machi gave the Red Sox a scare by giving up two runs on three hits in the bottom of the ninth to make it 5-4, but the defense was able to bail him out.

UP NEXT

The Red Sox and White Sox square off in Game 2 of the series Tuesday with a left-handed pitching duel. Wade Miley gets the nod for Boston, while Jose Quintana will start for Chicago. First pitch is scheduled for 8:10 p.m. ET.

Thumbnail photo via Twitter/@masslive