The second weekend of December was a busy one across three continents, with two world titles changing hands and needle-moving victories for many ranked contenders elsewhere.

Noel Mikaelian regained the WBC cruiserweight strap with a 12-round points win over three-division champion Badou Jack in Los Angeles, leaving the latter to ponder the possibility of retirement aged 42 seven months after their first meeting.

In Mexico City, Jose Salas scored a seventh-round stoppage of Landile Ngxeke to win the IBF bantamweight crown left vacant by The Ring's No. 7 pound-for-pound operator Junto Nakatani, who makes his 122-pound debut against Sebastian Hernandez on Dec. 27.

The Ring's No. 7-rated light heavyweight contender Imam Khataev returned to winning ways after his contentious points loss by David Morrell in July, stopping former title challenger Adam Deines in three rounds. Meanwhile former IBF world featherweight champion and The Ring's No. 5-rated 126-pound contender Luis Alberto Lopez brutally beat down Miguel Arevalo Mejia, also stopping him in three one-sided rounds during their Mexicali matchup.

Elsewhere, The Ring's No. 5-rated super middleweight contender Diego Pacheco endured adversity and a career-first knockdown before outpointing Kevin Lele Sadjo in Stockton, California.

On the same card, newly-minted WBO lightweight beltholder Abdullah Mason's next foe was all but set in stone after Joe Cordina's gritty points win over Gabriel Flores while former WBC featherweight queen Skye Nicolson won interim world title honours down at 122-pounds with a 10-round decision win over former world champion Yuliahn Luna Avila.

The evening prior, former unified cruiserweight beltholder Murat Gassiev's one-punch knockout of Kubrat Pulev for the WBA 'regular' heavyweight title stole headlines in Dubai.

Scroll down to see the various moves across three weight categories:

*Bold/italics denotes movement in the division.

Mikaelian rises two spots to No. 4, while Jack drops a place to sixth after his maiden loss at 200-pounds and first since consecutive 12-round decision defeats at light heavyweight in 2019.

C JAI OPETAIA Australia 29-0-0 (23 KOs)

1 GILBERTO RAMIREZ Mexico 48-1-0 (30 KOs)

2 CHRIS BILLAM-SMITH U.K. 21-2-0 (13 KOs)

3 MICHAL CIESLAK Poland 28-2-0 (22 KOs)

7 LEONARDO MOSQUEA France 17-0-0 (10 KOs)

8 ROBIN SIRWAN SAFAR Sweden 19-0-0 (13 KOs)

9 VIDDAL RILEY U.K. 13-0-0 (7 KOs)

10 BRANDON GLANTON U.S. 21-3-0. (18 KOs)

Unified champion and No. 1-rated Janibek Alimkhanuly is out after testing positive for banned substance meldonium before his proposed three-belt unification against Erislandy Lara earlier this month, meaning there's a new divisional leader in WBC beltholder Adames.

WBC interim titleholder Ramos, fresh from his 12-round points win over Shane Mosley Jr, is the new entrant at No. 10 while everyone else rises a spot.

C (vacant)

Despite a fourth-round stoppage win over solid opponent Herlan Gomez on December 6, former world champion Jason Moloney drops out of the 118-pound rankings with new entrant and IBF beltholder Salas sitting at No. 7. All those below him move down a space.

C (vacant)

1 SEIYA TSUTSUMI Japan 12-0-3 (8 KOs)

2 CHRISTIAN MEDINA Mexico 26-4-0 (19 KOs)

3 TAKUMA INOUE Japan 21-2-0 (5 KOs)

4 RYOSUKE NISHIDA Japan 10-1-0 (2 KOs)

5 DAIGO HIGA Japan 21-3-3 (19 KOs)

6 ANTONIO VARGAS U.S. 19-1-1 (11 KOs)