A look at who is unbeaten or winless in college basketball

The ranks of the unbeaten were thinned out even more Tuesday night.

Louisville, Maryland and Butler all lost for the first time, falling to Texas Tech, Penn State and Baylor, respectively. That left just five undefeated teams in all of Division I. There are also four teams that haven't won a game yet.

Here's a look at each of the remaining teams that are either unbeaten or winless.

First, the undefeated five:

OHIO STATE

Record: 9-0

AP Rank: 3

Pomeroy Rank: 1

Best Start Since: 2013-14. The Buckeyes started 15-0 but did not ultimately have a great season, losing in their NCAA Tournament opener as a No. 6 seed.

Highlight So Far: Ohio State won 74-49 at North Carolina in the ACC/Big Ten Challenge, handing the Tar Heels their most lopsided home loss under Roy Williams.

Why They're Unbeaten: Kaleb Wesson is a force, averaging 14.1 points and 9.3 rebounds a game, and the Buckeyes are holding opponents to 33.3% shooting.

Upcoming Challenge: Ohio State faces Kentucky on Dec. 21 in Las Vegas.

AUBURN

Record: 8-0

AP Rank: 12

Pomeroy Rank: 16

Best Start Since: The 1998-99 team started 17-0 and reached the Sweet 16.

Highlight So Far: The Tigers won a pair of games in New York late last month, beating New Mexico 84-59 and Richmond 79-65.

Why They're Unbeaten: The Tigers have picked up where they left off when they made it to last season's Final Four. Senior guard Samir Doughty is the team's leading scorer, and Isaac Okoro and Austin Wiley are shooting high percentages from the field.

Upcoming Challenge: Auburn hasn't had a marquee matchup on its schedule yet, but its Southeastern Conference opener at Mississippi State on Jan. 4 should be a tough one.

SAN DIEGO STATE

Record: 10-0

AP Rank: 25

Pomeroy Rank: 32

Best Start Since: San Diego State won its first 20 games in 2010-11. That Kawhi Leonard-led team lost only twice before the NCAA Tournament.

Highlight So Far: The Aztecs beat Creighton by 31 and Iowa by 10 on back-to-back days at an event in Las Vegas.

Why They're Unbeaten: Only two of their opponents have reached 70 points. The Aztecs were nearly knocked off by San Jose State this past Sunday, but a last-second 3-pointer by Malachi Flynn gave them a 59-57 win.

Upcoming Challenge: San Diego State already made it through one trip to Utah when it beat BYU on Nov. 9. The Aztecs head back to that state for a Jan. 4 matchup with Utah State.

DUQUESNE

Record: 8-0

AP Rank: Unranked

Pomeroy Rank: 68

Best Start Since: 1971-72, when Duquesne was also 8-0 under coach Red Manning.

Highlight So Far: The Dukes haven't been tested much, but they went to the Bahamas last month and beat Indiana State, Air Force and Loyola Marymount.

Why They're Unbeaten: The Dukes have six players averaging between 8.9 and 12.3 points per game, and center Michael Hughes already has 24 blocked shots.

Upcoming Challenge: Duquesne begins a stretch of four straight neutral-site games with an interesting matchup with Radford on Saturday.

LIBERTY

Record: 11-0

AP Rank: Unranked

Pomeroy Rank: 71

Best Start Since: This is the first time Liberty has started 11-0.

Highlight So Far: The Flames beat Radford 66-60 in their season opener.

Why They're Unbeaten: The Flames won an NCAA Tournament game last season, so this early success should be no surprise. They're outscoring opponents by an average of 13.1 points a game from 3-point range while shooting 42.1% from beyond the arc.

Upcoming Challenge: Liberty hasn't played a very tough schedule so far, but the Flames go on the road to face Vanderbilt on Dec. 14 and LSU on Dec. 29.