Crystal Palace are currently in fourth place in the Premier League table.
Zaha and Bolasie started the season slowly, but they are finding their groove now, and both played starring roles in the Eagles' 2-0 win over West Bromwich Albion over the weekend.
And Pardew believes that this up-turn in form has come because Sako has put so much pressure on them since arriving in the summer transfer window.
“He knew that there wasn’t a lot in it in terms of the choice between him and Sako,” Pardew admitted about Zaha's selection. “So did Yannick. That competition in the dressing room drives performances on. So Wilf and Yannick have a little debt to Sako this weekend.”
Sako joined Palace on a free transfer, and he has immediately made an impression at Selhurst Park, where his pace and power have added further quality to Pardew's attacking line-up.
Sako has played up-front and out-wide this season, and the Malian international has managed to score twice in his first five games.
The 27-year-old could have a tough job winning his place back form Zaha or Bolasie now that the pair have hit top form, though.
Towards the back end of last season, Bolasie and Zaha terrorised defences and when they are both on form they are one of the Premier League's most dangerous wing pairings.