The Celtics had their chances to win. Even late. Even after climbing all the way back from a 14-point deficit. But Al Horford’s last-second tip-in was deemed too late as the clock went off before the ball left his fingers. The Celtics fell 103-101 to the Bucks on Saturday at Fiserv Forum. Boston now trails Milwaukee 2-1 in the Eastern Conference semifinals, with a key Game 4 coming up at 7:30 p.m. Monday.