He excelled in the opening leg of the play-off against Spain, before a 3-0 loss in Oslo cost the Scandinavians a place in Portugal and Johnsen has since fallen behind Charlton's Thomas Myhre in the pecking order.
Johnsen began his career with IK Start, and helped them to promotion to the top flight in 1999, playing 21 games. The following campaign he made 22 appearances in the premier division for Start before Rosenborg swooped, paying an initial €800,000.
That move was eventually completed in January 2001, and while Johnsen knew first-team chances would be limited to begin with, he was certain he could learn from the sound displays of No1 keeper Árni Arason.
He made his Rosenborg debut in August 2001, keeping a clean sheet in a 6-0 home win against Moss FK. After remaining understudy to the reliable Arason for two seasons, Johnsen replaced the Icelander as the No1 in Trondheim for the 2003 season, when he helped the side clinch the domestic double, and he was ever-present the following campaign as Rosenborg retained the league title.