The second baseman led off Wednesday’s 9-3 win over the Orioles with a homer and propelled the Yankees’ newest free-agent treasure, Gerrit Cole, to his second win of the season.

LeMahieu’s homer was one of three hit by the Yankees and Cole showed long stretches of dominance, even if his final line wasn’t eye-popping.

Cole gave up three runs over 6 ²/₃ innings, walking two and striking out seven.

He had his Yankees debut delayed by four months and then his first start lasted just five innings against Washington due to rain.

The right-hander provided another glimpse of what the Yankees sought when they signed him in December to the richest contract ever for a starting pitcher — at least for most of his 102-pitch start.

On the night the Yankees had been scheduled — or rescheduled — to host their home opener against the Phillies, they instead faced the Orioles in Baltimore because Philadelphia was unavailable due to coronavirus concerns.

Cole was kept on regular rest despite the team’s lack of activity and walked the first batter he faced. He followed by allowing a run-scoring double two batters later — but then overpowered the Orioles, at one point retiring 14 straight and 19 of 20.

But after he got Hanser Alberto to pop to short for the second out of the seventh, Cole gave up a double to Renato Nunez followed by a two-run homer from Dwight Smith Jr. and a double by Pedro Severino to end his evening with a four-run lead.

Luis Avilan came on and walked DJ Stewart before getting Austin Hays to fly to right.

By then, the Yankees lineup added plenty of firepower and the combination gave the Yankees their 17th straight win over the hapless cellar-dwellers — and 16th in a row in Baltimore.

At least this time, Orioles’ fans didn’t have to sit through it in person.

The Yankees’ power display began immediately, starting with LeMahieu’s leadoff shot on the second pitch of the game against right-hander Asher Wojciechowski.

Wojciechowski allowed just four hits in his five innings, but three were home runs.

LeMahieu also added two singles and a double.

Aaron Judge opened the third with a home run to left and Aaron Hicks added a two-run homer later in the inning to give the Yankees a 5-1 lead and they never looked back.

It was also another victory for Cole, who extended his winning streak to 18 games.

Cole was sluggish early. Hays walked to start the bottom of the first and then Cole allowed a one-out RBI double to Jose Iglesias that cut the early Yankees’ lead to one run.

But Cole quickly settled in as the Yankees built on their lead.

Chad Green pitched a scoreless eighth before right-hander Brooks Kriske finished it in his MLB debut.

Cole’s next outing figures to come next week against the Phillies.