Nigerian striker, Taiwo Awoniyi grabbed a second-half brace to inspire Union Berlin to an excellent 2-1 win at Mainz on Sunday.
Despite firing blanks in his last three Bundesliga games, Awoniyi retained his starting spot at the MEWA ARENA in Mainz.
But he could only watch as Ingvartsen handed the hosts a deserved lead five minutes before the interval.
The 24-year-old had struck a fine effort in the 3-0 thrashing of Maccabi Haifa in the Europa League on Thursday and he showed his high confidence level when he pounced on a Max Kruse pass to draw Union Berlin level in the 70th minute.
The former Liverpool man then put the Iron Ones in the lead for the first time in the match four minutes later courtesy of a Behrens assist.