Sean Doolittle and his fellow members of the Nationals’ bullpen walked on the field before Game 1 of the World Series looking more ready for a round of golf, or a company picnic, than a baseball game.

“I wanted to look professional, so I put my collared shirt on,” Doolittle said Tuesday during a pregame interview on MLB Network at Houston’s Minute Maid Park. Doolittle sported a red polo shirt with a “Stay in the Fight” logo on the right breast. A few hours later, he earned the save in Washington’s thrilling 5-4 win over the Astros.

Nationals relievers have been wearing the polo shirts during batting practice since Game 4 of the NL Division Series against the Dodgers, when Washington trailed two games to one and was facing elimination. The Nationals haven’t lost since.

“We put ‘em on and we said it’s time to get down to business,” Doolittle said. “ … Guys look classy. We’re dressed for success. We’ve just been trying to have fun with this postseason run. A lot of us are going through this for the first time. There are a lot of nerves, there’s a lot of pressure, but this is one of the many weird things we have going around the clubhouse that keeps us loose.”

The shirts were custom made by Criquet, an Austin-based golf and lifestyle brand that counts actor Luke Wilson as a business partner. They were originally sent to Nationals Park as a gift for Nationals reliever Aaron Barrett, who is acquaintances with one of Criquet’s employees.

Criquet co-founder Billy Nachman said he was shocked to see Barrett and his teammates warming up in the shirts, which are 100 percent cotton and inspired by vintage golf wear, before Game 4.

“There’s not really a performance feature to these,” Nachman said with a laugh. “I thought maybe they’ll wear it to a news conference after, or get doused in champagne, but then they went out and wore them on the field.”

The Nationals won that night, 6-1, to force a deciding game back in Los Angeles. Of course Doolittle and his fellow relievers wore the shirts during batting practice before Game 5. The routine continued during a sweep of the Cardinals in the NLCS. Come first pitch, Washington has worn its navy blue alternate jerseys in seven straight games, all of them wins.

“As superstitious as baseball players are, they weren’t going to mess with that,” Nachman said. “They’re taking on this motto of getting down to business, taking care of business, and it’s a business trip.”

“You can get a quick nine in in the morning and be ready for lunch and stretch in the afternoon,” Doolittle joked before Tuesday’s game when asked about the shirt.

The ‘Stay in the Fight’ polo shirts aren’t available for sale, but there’s a plain red version for anyone interested in dressing like a Nationals reliever.

“I’m not a Nats fan or anything, but I’m definitely pulling for them now,” Nachman said. “Keep it going. We love pulling for the underdogs, and we know the Nats have a pretty awesome story this year. It fits the scrappiness of our brand.”

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