Washington Nationals’ lineup for second of three with the St. Louis Cardinals...

The St. Louis Cardinals walked Bryce Harper in three of his first four plate appearances in Monday’s series opener in Washington, D.C. but the Nationals’ 25-year-old slugger got his, with a game-tying two-run home run in the ninth and a walk-off sac fly in the the tenth that lifted the Nats to a 4-3 win.

And he did it all while continuing to battle an illness that led to a couple coughing spells over the course of the game.

“Huge day for him,” Davey Martinez said after the win. “Big pick-me-up for us. Those RBIs he picked up for us were awesome. Kudos to him.

“He’s playing through — like I said — he’s got a real bad cough. I don’t know if you guys see him, but he gets on the base and he starts — whatever is coming out is not good. I’m really proud of him.”

Gross.

Harper homered on a 3-1 fastball from Cards’ closer Greg Holland, then with runners on first and third with one out in the tenth, he got to a 2-2 count and hit a splitter low in the zone for the sac fly off left-hander Chasen Shreve, against whom he was 1 for 4 with a double, a walk and two Ks before Monday’s matchup.

Was he surprised the Cardinals didn’t walk him again?

“No, cause Shreve dominates me a little bit,” Harper told MASN’s Dan Kolko, “so was able to get the run in right there and win the ballgame.”

His manager was impressed with Harper’s approach in the tenth-inning plate appearance in particular.

“If you watched him, he got to two strikes and he spread his legs out and he almost had a two-strike approach which was really, really nice, and he knew that he just wanted to put the ball in play, and he did a great job,” Martinez said.

“Just trying to get the ball up,” Harper said. “Shrever is really good against lefties, and just trying to get a ball I could handle and was able to go into the outfield.”

As for the lingering illness? Martinez said he was actually a little concerned.

“I was hoping his lung didn’t come out really. He’s bending over and I’m like, ‘Holy moly,’ and then his last at bat he bent over too, I don’t know if you saw that, I’m thinking, ‘Oh no,’ you know. But he battled through it.

“After the game you want to hug him but you’re kind of ... ‘Alright, nice going.”

Martinez was acting out keeping his distance from Harper as he said that last part.

Harper’s back in the lineup tonight in spite of the health concerns.

HERE’S THE NATIONALS’ LINEUP FOR THE 2ND OF 3 WITH THE CARDS: