The two cases shocked the tennis world with many fuming at how they were handled by the authorities.
Players and pundits accused those overseeing tennis's anti-doing programme of double standards as they felt Sinner and Swiatek, who were both ranked number one at the time of their respective failed tests, had received preferential treatment.
Rattled by two failed drug tests in March for trace amounts of the anabolic androgenic steroid clostebol, Sinner endured sleepless nights over fears that a ban could stall his career, before being cleared of wrongdoing by an independent tribunal that accepted his explanation of unintentional contamination.
However, the men's world number one will go into the 2025 season facing a possible ban of up to two years after the World Anti-Doping Agency lodged an appeal with sport's highest court.
"It's in the head a little bit," Sinner admitted. "The most important thing is the people who are around me, who know me as a human being, trust me.
"That's also why I kept playing at the level I did. I was emotionally a bit down, a bit heartbroken. Sometimes life gives you difficulties and you just have to deal with it."
Sinner captured his first two Grand Slam titles at the Australian Open and U.S. Open to split the majors with Carlos Alcaraz.
Sinner also won the ATP Finals trophy before masterminding Italy's successful Davis Cup defence.
Triumphs in Rotterdam, Miami, Halle, Cincinnati and Shanghai meant Sinner had more titles than his six defeats but the doping saga put an asterisk on a stunning season in which he sparked a seismic shift atop the men's game to shut out Novak Djokovic.
'STRESS, ANXIETY'
On the women's tour, Swiatek dazzled with five titles that included her fourth French Open trophy, but was leapfrogged to the top ranking by Australian Open and U.S. Open winner Aryna Sabalenka, and ended the season with a month-long ban.
The Pole tested positive for trimetazidine but authorities accepted it was caused by contamination of her sleep medication melatonin, prompting 2019 Wimbledon champion Simona Halep to slam doping authorities after she had to battle to have her own ban reduced from four years to nine months.
"Both me and my team had to deal with tremendous stress and anxiety. Now everything has been carefully explained, and with a clean slate I can go back to what I love most," Swiatek said.
There were pleasant surprises too as Barbora Krejcikova won her second major at Wimbledon, Zheng Qinwen bagged Olympic gold, Coco Gauff wore the WTA Finals crown in its new home of Riyadh and Jasmine Paolini led Italy to Billie Jean King Cup glory.
GOLDEN GAMES
Perhaps no triumph meant more to a player than Djokovic winning Olympic gold, with the 37-year-old recovering after tamely losing to Alcaraz in the Wimbledon final to outlast the Spaniard in the Paris Games showpiece.
Victory reduced the Serb to an emotional wreck on the Roland Garros clay and once he managed to come up for air, he described the feat as his "greatest achievement".
With a career Grand Slam in the bag, the 24-times major champion will now look to eclipse Margaret Court's haul under the guidance of old rival and new coach Andy Murray, who ended his glorious career in Paris after an emotional farewell at Wimbledon.
There were more tears as 22-times major champion Rafa Nadal joined Murray in retirement, leaving Djokovic as the last active member of the "Big Four" that also included Roger Federer.
Nadal will be confident that the sport is in good hands, as heir apparent Alcaraz cemented his spot in the all-surface elite with magnificent French Open and Wimbledon wins to emerge as Sinner's main challenger.
