Pompey have had a fortnight to prepare for the match after their early exit from the FA Cup gave them a free weekend.
Izale McLeod's late strike secured a point against Coventry in their last outing, ending a run of seven straight defeats in all competitions.
And Whittingham feels his side are full of confidence as they prepare to take on the surprise pace setters.
"The break has given us a good amount of time on the training pitch to get our ideas across to the players," he told the club's official website.
"The result at Coventry was massive because the players have been working hard and they finally got something to show for that.
"Hopefully that can be the spark and we can kick on from here."