Carlsberg the Danish brewers attempted to sign him on behalf of Northamptonshire (where they had their UK base) and offered to double their countryman's wage.
"Stan", as his team-mates knew him, decided to stay at Derby because he "felt that we were going places under Kim Barnett's leadership and sincerely believed we were going to win some trophies".
[5] For Denmark, Mortensen appeared in four ICC Trophy tournaments (1979, 1986, 1990 and 1994), claiming 63 wickets at a mere 10.41 apiece, including a return of 7–19 in a one-sided match against Israel (who were bowled out for 45) in Nairobi in 1994.
From the 1984/85 English off-season Mortensen played for Brighton Cricket Club in Melbourne, Australia, taking 401 wickets at 13.00.
He represented Victoria against South Australia in a Christmas game which is an honour and probably his greatest achievement was to win the "R. M. Hatch Trophy" twice in 1986-87 and again in 1992–93.