Arsenal youngster Martinelli scored twice to inspire Arsenal to a 4-0 win against Belgium side St. Liege.
The 18-year old Brazilian converted a Tierney cross into the back of the net in the 13th minute of the match.
Three minutes later he curled the ball into the far end of the post making it two nil at the joy of home fans.
Fellow youngster Willock made it three before half time and six minutes after Martinelli’s double sending the gunners with an advantage.
In the second half Martinelli set up an incredible cross that was well sent to the back of the net by Ceballos.
Aubameyang came in to strengthen the strike force and probably claim a goal under his superb form he is in.
Unai Emery had initially casted a doubt on the club’s performance given the selection he had brought in the Europa League tie.
Little was expected until when the youngsters created many chances and over powering the Belgium’s.
The win see Arsenal top their group with six points from two consecutive wins in the Europa League.
Most of the first eleven players were rested following 1-1 draw against rivals Manchester United on Monday.