Someone had asked earlier about the history of us having a favorable upset in our region when we were a decently high seed, such as #11 Duquesne upsetting #6 BYU. Since the modern seeding started in 1985, this is the history. Limiting it to top 5 seeds, since a #5 seed is more or less the same as a "protected" #4 seed.
1985: #3 Illinois makes Sweet Sixteen. No upsets, we had to beat #6 Georgia and lost to #2 Georgia Tech in the Sweet Sixteen.
1986: #4 Illinois loses Second Round. No upsets, we lost to #5 Alabama in the Second Round and would have had to play #1 Kentucky in the Sweet Sixteen.
1987: #3 Illinois loses First Round. Yes, we all know the Austin Peay disaster. However, there were no upsets waiting ... we would have had to beat #6 Providence and #2 Alabama.
1988: #3 Illinois loses Second Round. No upsets, we lost to #6 Villanova in the Second Round and would have faced #2 Kentucky.
1989: #1 Illinois makes Final Four. Zero upsets, after our First Round win, we beat #9 Ball State, #4 Louisville and #2 Syracuse to get to the Final Four.
1990: #5 Illinois loses First Round. While we would have had to beat #4 Arkansas in the Second Round, #8 seed North Carolina knocked off #1 Oklahoma in our region ... and proceeded to lose by 23 to #4 Arkansas. And then #4 Arkansas made the Final Four by beating #10 Texas in the Elite Eight because of two upsets in the bottom of the bracket.
1998: #5 Illinois loses Second Round. No upsets, we would have had to beat #1 Arizona if we got past #4 Maryland.
2000: #4 Illinois loses Second Round. No upsets, #5 Florida (who beat us) had to go through #1 Duke and #3 Oklahoma State to make the Final Four.
2001: #1 Illinois makes Elite Eight. No upsets, we ran through #4 Kansas in the Sweet Sixteen before going down to #2 Arizona (the first Illini game I remember).
2002: #4 Illinois makes Sweet Sixteen. As another poster mentioned, we WERE helped out here by #12 Creighton taking down #5 Florida in the First Round.
2003: #4 Illinois loses Second Round. No upsets, if we had beat #5 Notre Dame, we'd have #1 Arizona waiting.
2004: #5 Illinois makes Sweet Sixteen. No upsets, we beat #5 Cincinnati (like a drum!) before falling short vs. #1 Duke.
2005: #1 Illinois makes National Championship Game. After beating #9 Nevada, we did get to face #12 UW-Milwaukee (who had just knocked off #5 Alabama and #4 Boston College).
2006: #4 Illinois loses Second Round. While we would have had to beat #1 UConn in the Sweet Sixteen, #11 George Mason waited in the Elite Eight.
2021: #1 Illinois loses Second Round. Frustrating missed opportunity ... if we got past #8 Loyola, we would have faced #12 Oregon State for a trip to the Elite Eight.
2022: #4 Illinois loses Second Round. No upsets, we had #1 Arizona waiting.
TL;DR
So, 2024 (#11 Duquesne standing between us and a Sweet Sixteen) is one of the most favorable setups we have ever had to make the Second Weekend. GET IT DONE!
P.S. I was not around for 1990, but MAN that one seems like a huge wasted opportunity. We lost by 2 to #12 Dayton who then lost by 2 to #4 Arkansas ... who would go on to the Final Four.