The Welshman claimed Britain's first win in the competition with victory in the 400 metres to add the Cup title to his AAAs and European Championships successes.
Thomas then immediately began preparing for next week's Commonwealth Games where he will attempt to defy the odds and snatch the gold in Kuala Lumpur from his refreshed rival Mark Richardson.
"I won't have any problems getting myself up mentally for the Games, but physically it could be difficult," said Thomas.
"Mark is out there already and he will have had plenty of rest. But as soon as I get that Welsh vest on then I will give it my best shot.
"It would be incredible if I could win the AAAs, European, World Cup and then the Commonwealths all in one season. But even if I don't win gold it's still been a great year for me, better than I could have imagined after a poor start when Mark looked as though he was going to win everything."
Thomas is considering investing some of the prize money in a business- class upgrade for the flight to Kuala Lumpur - he won't arrive until the early hours of Tuesday and faces two rounds of the 400m the next day.
"I've started going to bed earlier to try and get myself on to Malaysian time because that might help avoid the jet-lag, but I know it is not going to be easy," he said.
The 24-year-old avenged his defeat by Jerome Young in last weekend's Grand Prix final in Moscow as he caught the American by the 100m mark then hung on in the final metres. Thomas proceeded to bring up his breakfast after clocking 45.33 seconds to beat Young, second in the world rankings this year, by 0.04 of a second with Troy McIntosh third for the Americans in 45.45.
"That was the hardest race I've had all year," admitted Thomas, who set a then Welsh record on the Johannesburg Stadium track in 1996. My plan was to catch Young and put him under pressure, then it was a case of hanging on. The line just wouldn't come quickly enough.
"That was the first race where I've realised I'm not running for Iwan Thomas, I'm running for Great Britain. I'm not a young punk now just there to pick up a couple of points. I was expected to get a win."
Britain's sprint quartet of Allyn Condon, Marlon Devonish, Julian Golding and Dwain Chambers maintained the winning momentum on the second day of the eighth World Cup and they will share a $60,000 bonus. The foursome clocked 38.09 seconds to beat a second-rank United States team (38.25) with Africa third in 38.29.
But there were other fine performances, led by Anthony Whiteman who narrowly missed out on victory in the 1500m when finishing third in 3:40.99, just 0.12 adrift of the winner Laban Rotich. Europe's Rui Silva was second in 3:40.95.
The discus thrower Bob Weir produced a season's best of 64.39m to be placed fifth, as was Christian Stephenson in the 3000m steeplechase (8:55.67). Both finished higher than expected.
Mike Edwards was sixth in the pole vault after following team orders and successfully clearing a low opening height to avoid a repeat of the European Cup when he failed to score a point.
It all helped Britain's men, who were seventh after the opening day, to move up to sixth place with 59 points. The holders Africa lead with 82 points from Europe (76) with Germany third (70).