The Cod Army are currently five points behind Bradford in the last play-off spot with two games remaining.
The first of those is the clash with fellow play-off hopefuls Chesterfield on Saturday.
Alexander said: "Wins in the last two games would put us right up there.
"A few teams are clinging on in hope of a slip up amongst the teams just above and ourselves and Chesterfield are in that group.
"It's going to be a challenge. Chesterfield play good football and I know Paul Cook from his time at Burnley and his Accrington Stanley days as manager.
"Paul likes his teams to get the football down and play attractively."