Two judges awarded the fight to Porter by scores of 116-112 and 115-113, while the third saw Ugas as a 117-111 winner.
Known for his rags-to-riches climb from the street, Pacquiao said his wife Jinkee was adamant their 19-year-old son, nicknamed Jimuel, must not box.
The 33-year-old, who as a middleweight won Olympic gold in Beijing in 2008, said he had been on an "amazing journey" but 10 years to the day of his first professional bout was an apt one to hang up his gloves.
The action-packed bout was stopped in the 10th of 12 scheduled rounds on the advice of the ringside doctor because of a gaping cut over Dirrell's left eye.
Unbeaten Davis lived up to his knockout-artist reputation with his 20th win inside the distance out of his 21 victories.
The 35-year-old Kovalev won by a 12-round unanimous decision to avenge a stunning loss to Alvarez six months ago and retake the World Boxing Organization 175-pound belt.
The 24-year-old Xu went on the offensive landing solid combinations and forcing Rojas to go into a defensive shell for several rounds.
The AIBA is being investigated by the International Olympic Committee which in November froze preparations for boxing at next year's Games, warning it could be stripped of the right to run the competition.
The New York Daily News had reported that some in the Filipino legend's camp feared he had suffered a potentially career-threatening detached retina.
Pacquiao was set to fly home to the Philippines on Monday for an exam by an eye specialist, according to the newspaper, which cited two unnamed sources from Pacquiao's camp with different takes on the injury.
The Filipino star is now hoping to avenge his 2015 loss to Mayweather which became the richest one-day sporting event in history.
American Plant knocked Uzcategui down twice as he dominated the early rounds then faded over the last few but managed to hold on for the crown at the Microsoft Theater in Los Angeles.
Kom capped her 2018 campaign with her sixth world championship title after defeating Ukraine's Hanna Okhota by 5-0 in Delhi.
Mayweather floored Nasukawa, a kickboxer less than half his age, three times in the first round of the three-round contest before the Japanese fighter's trainer rushed in to stop the fight.
The 41-year-old unbeaten champion has been tempted out of retirement -- again -- for a one-off "exhibition" in Saitama, north of Tokyo, against "Ninja Boy" Nasukawa, a fighter more than half his age at 20.