The 23-year-old striker continued his torrid form in 2013-14, as his brace helped send AZ to the quarterfinal of the KNVB Cup.
The goals were Johannsson's fourth and fifth in just two Dutch Cup games, and 16th and 17th in all competitions this season. He also made his penalty kick in the shootout for good measure, as AZ moved onto the quarterfinals.
After Heerenveen took an early lead, the Icelandic-American striker opened the scoring for his team with a rebound tap-in with 19 minutes on the clock. The teams entered extra time tied 1-1 and Johannsson appeared to have scored the winner in the 105th minute, as he muscled off a defender in the box and slotted home.
However, Heerenveen's Hakim Ziyech scored his second of the game from the penalty spot with just seconds to play, sending the round of 16 tie into a shootout, where AZ would eventually progress after going into sudden death.