Swanigan had 21 points and a career-best 21 rebounds, Haas scored 18 points and the 15th-ranked Boilermakers beat Western Illinois 82-50 on Monday night.
Swanigan went 7 for 16 from the field and 6 for 7 at the free-throw line in his ninth double-double of the season. He had 26 points and 10 rebounds in Saturday's 86-81 victory against No. 25 Notre Dame in the Crossroads Classic.
"It's the mindset I have every game," said Swanigan, who accomplished his impressive line in just 28 minutes. "You have to go every time, and that's what I try to do every game. We just keep coming at you in waves. We are used to it, because we practice against each other every day."
Purdue (10-2) also got 16 points from Vince Edwards in its fifth consecutive victory.
Mike Miklusak, an Indiana native who attended high school 85 miles from the Purdue campus, led Western Illinois (3-8) with 16 points and 11 rebounds. Western Illinois shot 31 percent (19 for 61) from the field.
The Boilermakers improved to 6-0 all-time against the Leathernecks.
Swanigan, Haas and Vince Edwards combined for 33 points and 17 rebounds in the first half, helping Purdue to a 44-28 lead at the break.
"There were a lot of rebounds to be had tonight, but Caleb plays really hard," Purdue coach Matt Painter said. "It's contagious when your best player plays harder than everybody else. Basketball means a lot to him. There are lots of demands once a player gets to college, but he puts in the extra work every day."
The Boilermakers raced out to a 13-3 lead, but Western Illinois closed to 27-22 with 6:16 remaining on a 3-pointer from Miklusak. The Boilermakers then responded with a 12-0 run.
Western Illinois: The Leathernecks showed an ability to shoot 3-pointers, going 8 for 15 from beyond the arc in the first half, but are a sub-.500 team in large part because their interior players lack the size or skill to play with teams whose low-post players are the focal point of the offense, like Purdue.
Purdue: Big Ten Player of the Week Swanigan continues to dominate at both ends of the floor, a big reason why the Boilermakers are unbeaten since a Nov. 30 loss at Louisville. If Purdue defeats Norfolk State on Wednesday, it will take an 11-2 record into the Dec. 28 Big Ten opener against Iowa.
Swanigan, whose nickname is "Biggie," is averaging 20 points and 13.7 rebounds in the past three games, making 24 of 43 field-goal attempts against Cleveland State, Notre Dame and now Western Illinois.
Western Illinois: The Leathernecks don't play again until Dec. 29 when they visit Fort Wayne.
Purdue: The Boilermakers host Norfolk State on Wednesday night.