Ellis added nine rebounds, eight assists, three steals and matched a career high with three blocks for Milwaukee, which outscored Portland 31-8 in the second quarter—the Trail Blazers' fewest points in any period this season. The Blazers shot a woeful 2 for 20 from the field and had six turnovers in the quarter.
The Bucks took a 58-31 lead into halftime before Portland fought back with 64 second-half points to make things interesting.
Wesley Matthews hit seven 3-pointers and scored 28 points, and LaMarcus Aldridge added 21 points and
Portland, coming off a one-point loss at Philadelphia on Monday, made a game of it before running out of time.
Nicolas Batum hit a 3-pointer from the left wing to cut Milwaukee's lead to 96-88 with 2:36 to play and Matthews added another to get Portland within 100-93 with 1:33 remaining, but Aldridge lost the ball in the paint on the Blazers' next possession.
Portland missed its next two 3-point attempts before Jennings sank two free throws with 26.2 seconds to play to seal it.
Milwaukee opened the second quarter with a 16-0 run, while Portland missed its first 10 shots of the period. The Bucks held a 27-23 lead when J.J.
Three of Milwaukee's next four baskets were layups, including one by Gustavo Ayon that capped the 16-0 run and gave the Bucks a 43-23 lead with 6:40 remaining in the half.
It took until 6:03 remained for Portland to finally score on two free throws by J.J. Hickson. Aldridge's tip-in with 3:56 to go was Portland's first made basket in the second.
It was so bad for Portland, Hickson accidentally threw the ball off Matthews trying to save it from going out of bounds with about 2:40 left and Matthews' baseline dunk attempt was blocked by Ellis with 46 seconds left.
Portland scored 12 of the first 14 points of the third quarter to get the deficit down to 60-43 on a layup by Batum with 8:35 to play, but a 3-pointer by Redick capped a 12-3 run that gave the Bucks a 77-57 lead with 4.5 seconds left.
Notes: Milwaukee's Luc Mbah a Moute (sprained toe) and Ersan Ilyasova (left hip pain) did not play. Ilyasova finished with 27 points and 14 rebounds in a 110-104 victory at Portland Jan. 19. . Portland's previous low for points in a quarter was 12, set three times this season. . Samuel Dalembert scored 10 of Milwaukee's first 14 points. . Portland fell to 9-25 on the road. . Milwaukee has won four straight games against Portland for the first time since the 1984-85 season. . The Bucks are 41-16 against Portland at home.