When Minnesota United acquired defender Ike Opara from Sporting Kansas City last winter, it did so in good part because of the veteran's height and his head.

You could see why when the 6-2 Opara scored United's only goal — its first on a dead-ball set piece this season — on a header against Seattle on Saturday night at Allianz Field, right?

"I was more inclined for our end than the other end, but he's a big body, isn't he?" United coach Adrian Heath said.

Heath wanted Opara to protect his team's goal. But Opara also finally proved United's set-piece ability dangerous when he scored the game's first goal, one that he didn't see succeed after his head beat Seattle defender Chad Marshall's head to the ball.

Well, he sort of won that contest.

"I got one, but I didn't know it because of my nose," Opara said. "But whatever, I'm just glad it went in."

Ike Opara scored a big goal for United with his headwork rather than footwork, and paid the price despite his protective headband.

He didn't know because their heads collided just as Opara leapt at the goal box's corner and headed Jan Gregus' free kick from 36 yards away. Opara got enough of the ball with his head to direct it into the goal's far corner, and he got enough of Marshall's head to get a bloody nose.

Opara needed some gauze stuffed up a nostril to stem it.

"That was Chad's back of the head; it's a hard head," Opara said. "This one hurt so bad. Normally, I can celebrate it through it."

The 2017 MLS Defender of the Year, Opara has had his issues with heads the past three weeks. He banged them with a New York City FC defender late in Allianz Field's debut and needed seven stitches to close the gash over his eye and a week's rest to recover from the injury.

"I can't buy one, but you know what: I'm still standing," Opara said. "So that's all that matters."

He has worn a protective head band the past three games, but even that wasn't enough when his head and Marshall's converged.

"Maybe I need something with a facemask," Opara said.

He has been fearless with or without one, scoring his first goal with United. Seattle's Cristian Roldan countered with a beautiful 24-yard blast just before halftime that proved to be the last of the night's scoring in the Loons' 1-1 draw with the Sounders.

"Ike's incredibly athletic and he's determined," Heath said. "If we put the ball in the right spot, he's difficult to mark."

Gregus put his free kick in the right spot. Until then, United hadn't scored a goal this season off such a situation, by either a corner kick or free kick.

"If you put it in the right area and you have size and you want to go and head it …" Heath said. "You want to attack the ball and show a little determination at the end of it like Ike did for the goal. We looked dangerous again in some of the set pieces."

Opara nearly scored a second goal, but his header off Gregus' corner kick was deflected by traffic in front of the goal, as was Eric Miller's ensuing chance in the 66th minute.

When United went small with its substitutions and pushed to win, Seattle went big with its subs. The Sounders headed two balls nearly in succession off the post in the 82nd minute.

That enabled the Loons to stay unbeaten at Allianz Field, but it was their third draw in four home games.

"We had the opportunity to win this game if we just had kept doing what we were doing," Opara said. "Then the game flips on its head and we were grateful to get out of here with a draw. The lack of discipline we had to push for the win is one reason we almost lost tonight.

"We're happy to get out with a point, sadly. It's not nice to settle at home, but we need to build from this moving forward."