Claressa Shields-Savannah Marshall, Mikaela Mayer-Alycia Baumgardner live boxing results and analysis

Claressa Shields is once again the undisputed middleweight champion of the world.

Shields defeated Savannah Marshall by unanimous decision, 96-94, 97-93, 97-93 at the O2 Arena in London on Saturday night to retain the WBC, IBF and WBA belts and win the WBO belt in a high-action, close fight.

For Shields, it avenges her only loss in a boxing ring — a decade ago as an amateur. Shields outlasted Marshall, 174-132 and landed a higher percentage of punches, 37 to 34.

Read full recap here ...

Round 10: Marshall appeared to land a little more and be a little more aggressive in the final round. Very, very close round but have to give it to Marshall. Marshall 10-9. Shields 96-94.

Round 9: Marshall was more aggressive this round, and while she didn't put Shields in trouble at all, she appeared to handle the round well. Marshall 10-9. Shields 87-84.

Round 8: Shields was the clear aggressor in the round and landed what looked like the two best punches of the round as well. Shields 10-9. Shields 78-74.

Round 7: Another close round and while Marshall looked like she threw a lot, it didn't look like any of those landed clearly. Shields, meanwhile, landed some body work as she's done all fight. Shields 10-9. Shields 68-65.

Round 6: Close round, but Marshall landed perhaps the biggest punch of the round. This round could go either way. But Marshall might have edged this round here. Marshall 10-9. Shields 58-56.

Round 5: Marshall had her best 30 seconds of the fight to open the round. The body work from Shields helped her rebound a bit as did a strong hook at the end of the round, but it felt like Marshall's best round. Marshall 10-9. Shields 49-46.

Round 4: Maybe the closest round so far. Marshall had some good offensive moments, but