Whittingham believes that another victory at home to Stoke City on Saturday will give him and his teammates plenty of momentum heading into the final few weeks of the campaign.
"We've been confident of staying up but a win like that [against Southampton] makes us even more confident," the 29-year-old told The Sun.
"It's not impossible staying up. If we can beat Stoke it opens things right up for us."
Cardiff and Stoke played out a goalless draw when the teams met at the Britannia Stadium back in December.