NEW YORK—Either Xavier or Creighton will reach the championship game of the Big East tournament in its first year in the conference.The two newcomers will meet in Friday night’s semifinals in a game that will feature two unanimous first-team All-Big East selections.Semaj Christon had 18 points for third-seeded Xavier in its 68-65 victory over Marquette on Thursday night. Doug McDermott, the nation’s leading scorer with a 26.5 average, had 35 points in the second-seeded and 14th-ranked Bluejays’ 84-62 quarterfinal win over DePaul.Justin Martin scored 19 points for the Musketeers (21-11), who moved to the Big East from the Atlantic 10.Matt Stainbrook scored down low with 4:32 to play to give Xavier a 57-51 lead and that would be the Musketeers’ last field goal of the game as they went 11 of 14 from the free throw line to hold off sixth-seeded Marquette (17-15), which lost its fourth straight.Deonte Burton had a career-high 23 points for the Golden Eagles and Todd Mayo added 21.