In shades of a former nightmare, Southampton was reduced to 10-men after Jannik Vestergaard was shown a straight red for a foul on Jamie Vardy.
The Dane appeared to have gotten the ball before the man, but was adjudicated with no help from VAR to have denied a clearing scoring opportunity when he clashed into Vardy.
Saints got their chance from the spot after Kelechi Iheanacho handled the ball in the area and Ward-Prowse made no mistake firing past Kasper Schmeichel from the spot to make it 1-0 for his eighth goal of the league campaign.
Iheanacho atoned for his mistake, however, when he picked out Evans for the equaliser in the 68th minute as the defender headed home from six yards out.
Southampton had to hold on for a valuable point with Alex McCarthy denying Vardy from point-blank range after the forward turned his defender inside out in search of a late winner.
Wilfred Ndidi then saw his effort the edge of the area blocked behind with Saints packed tightly into their own box.
Southampton temporarily climbed into 14th place on 37 points with five games remaining in the season.
Southampton (4-4-2): McCarthy; Stephens, Vestergaard, Bednarek, Walker-Peters; Tella (Salisu 15), Armstrong, Ward-Prowse, Minamino (Diallo 76); Redmond, Adams (N’Lundulu 90+2)
Unused subs: Forster (GK), Walcott, N’Lundulu, Ferry, Djenepo, Ramsay, Jankewitz
Goals: Southampton (60)
Bookings: Vestergaard (RED 10), Minamino (50)
Leicester City: Schmeichel; Soyuncu, Evans, Fofana (Perez 45); Thomas (Albrighton 69), Tielemans, Ndidi, Castagne; Maddison; Vardy, Iheanacho
Unused subs: Ward (GK), Mendy, Pereira, Praet, Amartey, Choudhury, Under
Goals: Evans (68)