Tim Weah was the difference maker in the 79th minute. (Bill Streicher-USA TODAY Sports)

TYCHY, Poland – The United States secured a berth in the Under-20 World Cup knockout round with a 1-0 victory over Qatar Thursday.

Forward Tim Weah tallied in the 79th minute off of an assist from Alex Mendez.

The Americans finished second in Group D and will face the winner of Group E in the Round of 16 in Bydgoszcz Tuesday. The USA will learn its opponent for the Round of 16 Friday after the final matches of Group E. The U.S. squad will face the Group E winner, either France or Mali, at 11:30 a.m. ET (5:30 p.m. local time).

Ulysses Llanez came on as a U.S. substitute in the 63rd minute to provide an instant attacking spark and some opportunistic play from Alex Mendez in the 76th minute set up the game’s lone goal.

As Qatar tried to play out, Mendez rushed in to poke the ball out from a Qatari defender and play it up to Weah. The son of Liberian great George Weah hit a shot over the sliding Shehab Mamdouh to put the U.S. on the board.

In the game’s final minutes, the U.S. was awarded a penalty kick after Brandon Servania was taken down into the box. Mendez attempted the spot kick, but Mamdouh made a leaping save to deny the attempt.

Despite dropping its first two U-20 World Cup matches, Qatar came out undeterred in a fierce first half. A U.S. team that dominated possession in each of its first two games in Poland saw Qatar hold the ball for spells and threaten in transition.

While Brandon Servania sent a shot at Mamdouh in the early going, the U.S. had trouble establishing its rhythm as goalkeeper David Ochoa, making his first World Cup start, was called into action a number of times. Center back Chris Richards did well to steady the back line against a number of Qatari forays into the final third.

After the break, several stops and restarts interrupted the flow of the game. Ochoa made a few other fine saves to open the half and while the U.S. earned several corner and free kicks from dangerous spots, the Americans weren’t able to convert the opportunities into goals. Two direct free kicks from just above the 18-yard-box from Alex Mendez sailed just high and wide.