The Canadians overcame a 26-point effort from the Dallas Mavericks superstar to reach the final four for the first time, where they will face Serbia on Friday.
The result also meant Serbia and Germany qualified for the Paris Olympics as the highest-placed European teams at the World Cup.
Doncic, who also had five assists and four rebounds, was ejected in the fourth quarter for picking up his second technical foul.
Canada's Dillon Brooks was also ejected earlier in the fourth quarter.
Brooks and Doncic were engaged in a ferocious tussle throughout the game.
The Manila crowd, getting their first look at Doncic in the flesh, cheered the Slovenian superstar's every move and booed Brooks.
Brooks responded by blowing a kiss to the fans after nailing an early three-point shot.
The two teams refused to give an inch and were locked at 50-50 at the half-time break.
Canada began to edge ahead after the interval, helped by a timely three-pointer from Brooks that gave his team a seven-point lead.
Shai Gilgeous-Alexander had 31 points to lead Canada in scoring, followed by RJ Barrett with 24.
Germany beat Latvia in the day's first quarter-final to set up a semi-final showdown with the United States.
