The 25-year-old, who was defending her Wimbledon title, was eliminated in the third round by Alexandra Eala of the Philippines.
Poland's second-highest-ranked player, Maja Chwalińska, slipped one place to No. 22 after a first-round defeat, according to the latest rankings released by the Women's Tennis Association (WTA) on Monday.
Chwalińska did not qualify for the Wimbledon main draw last year.
Fellow Pole Magdalena Fręch remained at No. 44, while countrywoman Magda Linette climbed eight places to No. 51.
Belarus' Aryna Sabalenka retained the No. 1 ranking despite a fourth-round loss at Wimbledon.
The gap between Sabalenka and second-ranked Elena Rybakina of Kazakhstan narrowed after Sabalenka failed to match last year's semifinal showing.
In the WTA Race to the Finals, which counts only points earned this season, Świątek is 12th with 1,954 points, while Chwalińska is 21st with 1,464.
Russia's Mirra Andreeva leads the standings with 4,999 points.