WATCH: Manchester City's American prospect Cavan Sullivan scores twice, grabs two assists in Philadelphia Union's CONCACAF Champions Cup blowout win

The 16-year-old started his first game of the season, and repaid manager Bradley Carnell's faith in style with his best performance in a Union shirt to date. The Union were 2-0 up by the time Sullivan worked his magic for the first time, flicking deftly into the path of Stats Korezeniowski, who made a mistake to give the MLS side a 2-0 advantage after just 12 minutes. 

He was in and out of the game for the remainder of the first half, but came alive in the second. He set up Ben Bender to make things 5-0 after 53 minutes, before adding two late goals of his own - both routine finishes inside the box - to round off a CONCACAF thrashing at Subaru Park. They were the first and second strikes of his Union career to date. 

Sullivan has made a habit of breaking records since signing a homegrown contract at 14-years-old. He was the youngest debutant in American soccer history when he appeared for the Union on July 17. And he added another for the history books Thursday night, becoming the youngest American to score a goal in the CONCACAF Champions Cup, aged 16 years, four months, and 29 days.  

What role he plays this season remains to be seen. The Union are admittedly covered at his spot, with experienced midfielders Indy Vassilev and Danley Jean Jacques ahead of him in the pecking order. But with Philadelphia playing in three competitions - with the additional wrinkle of a World Cup break - the highly-touted youth prospect will certainly have a role to play in some capacity. As part of his homegrown contract with the Union, Sullivan has a pre-arranged transfer to Manchester City when he turns 18. 

He played 20 minutes of the Union's season opener, a 1-0 loss to D.C. United last Saturday. 

The Union, meanwhile, advance top the next round of the CONCACAF Champions Cup. They will face Mexican giants Club America in the second round of the tournament. The first leg is set for March 10 in Philadelphia, before a tricky away fixture eight days later in Mexico City. Should they advance, the Union will face the winner of Inter Miami and Nashville.