Minnesota United won Saturday's international friendly 4-3 over Germany second division SC Paderborn 07 at Allianz Field, but lost former MLS All Star and veteran defender Romain Metanire to another concerning hamstring injury.

Loons second-team midfielder Aziel Jackson's first first-team goal in the 75th minute — a perfectly struck free kick from 22 yards away — stood as the winner, even after the Bundesliga 2 team scored five minutes later with a goal that pulled them within a goal.

Jackson starred on a night Loons coach Adrian Heath's starting 11 and generous substituting provided opportunity for second-team players such as Jackson and young goalkeeper Fred Emmings.

Emmings made his first-team debut to start the second half, just three days after he graduated from high school.

"Crazy week," Emmings said. "Lots of emotions."

Jackson's goal brought victory, but Heath afterward lamented Metanire's injured left hamstring on which he came up hopping in pain in the 26th minute.

Metanire had played just 22 minutes all season — all in an April 10 game at Austin FC — because of a hamstring torn in last season's first-round playoff loss to Portland.

That was his right hamstring. Saturday, he injured his left on a night teammates Kemar Lawrence and Niko Hansen also left the game injured.

"The disappointment has been Romain, and it's not even the one that he has had problems with," Heath said "It's the other leg, hamstring again. That's disappointing."

Despite "all the good things" Heath saw in the 4-3 victory, he was troubled by Metanire's injury.

"It's going to be concerning because if it's a bad one, chances are most of this season is going to be a washout for him, really," Heath said. "He just hasn't been able to get going. We'll have a better idea how he is in the next couple days, but it doesn't look good at this moment in time."

Jackson scored on a perfectly struck free kick over which he, veteran Adrien Hunou and young Joseph Rosales each talked about taking.

"I was happy I got to take it, I was saying I want to take it," Jackson said. "I feel confident. It's tough on the field. There's so much adrenaline. Everyone wants to do more for the team. I just wanted to step up and take the responsibility. I felt like I just had to get it over the wall.

"It was a big wall, so I had to hit it really high and luckily it went down and into the net."

The Loons led 1-0 on defender Bakaye Dibassy's flicked-on corner kick goal, 2-1 on starter Jacori Hayes' left-footed strike just before halftime and then 3-2 on starting striker Luis Amarilla's first goal since March 19 in the 61st minute.

"Good to see Luis get a goal," Heath said. "When you're goal scorer like he is, you live and die by your goals. He has been very frustrated. As I said to him in the week, you have to keep believing in yourself, like we do believe in him. His opportunities will come."