The 23-year-old Welshman established himself as the man to beat in Paris with a time of 45.39sec - 0.17sec inside Todd Bennett's 12-year-old mark - which has been bettered by only four men: Michael Johnson, Danny Everett, Thomas Schoenlebe and Butch Reynolds.
With none of these due to compete on 7 to 9 March, Baulch's prospects for gold look bright, especially given his victory over the reigning world indoor champion, Darnell Hall of the United States, in Stuttgart the previous weekend.
"I felt like Michael Johnson when I crossed the line," said Baulch, throwing his arms up as he recalled the moment: "I was really shocked I'd run that quick."
Baulch claimed he had been pushed to his seventh personal best of the season by the presence of the man who finished second in 45.83, Mark Hylton. "I ran like a scared rabbit," he said.
Hylton, who collected an Olympic silver medal with Baulch in the relay last summer, has also made huge strides this season. Yesterday was his sixth personal best of the season and he, too, has medal chances in Paris.
With the third and fourth men home, Guy Bullock and Richard Knowles, also running personal bests of 46.11 and 46.92 respectively, Britain's chance of winning the 400 and relay is, in Baulch's own exuberant words "very, very, very good."
Baulch recalled watching Bennett setting what was then a world best in winning the European indoor title in Greece. "I remember watching Todd on television and thinking: `I'd love to do that.' I'm really proud. It's been a good day."
It was a good day, too, for Doug Turner, who lowered his national 200m record to 20.61sec. Turner's coach, Jock Anderson, also trains greyhounds. His athlete was swiftly out of the traps yesterday to produce a performance that makes him an outside medal contender next month.
The Welsh had a profitable weekend, providing two other winners on Saturday in Colin Jackson - who looked in promisingly smooth form as he won the 60m hurdles in 7.54sec - and Hayley Parry, a 23-year-old Swansea schoolteacher who beat Diane Modahl in the 800m.
Britain's prospects of success in the 60m rest on the powerful shoulders of Jason Livingston, whose victory in 6.55sec gave him the chance to become the first athlete to represent Britain after being banned for steroid abuse.
Saturday's performance by the 25-year-old, who returned to competition last June, was the third fastest in the world this year. Canada's Olympic 100m champ Donovan Bailey, who ran 6.51 to beat Michael Green of Jamaica by 0.01sec in Tokyo on Friday night, will be clear favourite if he competes in Paris. Livingston is happy just to be there, and plans to frame his British vest. "I've dreamt about this for a long time," Livingston said. "I've suffered for it for four years."
Malcolm Arnold, Britain's chief coach, paid tribute to Livingston's perseverance in returning to the sport. "To a degree, I've got to admire him," Arnold said. "A lot of people wouldn't have bothered. But he wanted to come back and prove himself, so good luck to him."
His sentiments were not exactly echoed by Sally Gunnell, who did enough to qualify by finishing second to Phyllis Smith in the 400m in what was only her second competitive outing since being carried from the Olympic track.
She said that her reaction to athletes returning to the sport after four- year bans was unchanged: "I still believe that you should have a life ban for offences like that."
Steve Smith, the Olympic high-jump bronze medallist, beat Dalton Grant, clearing 2.30m to reverse Friday's result in Germany, where Grant cleared 2.33. Both are capable of winning gold.
That ambition is well beyond the winner of the women's 1500m, Shirley Griffiths, but she nevertheless produced one of the best efforts of the weekend as she took four seconds off her personal best to finish in 4min 14.98sec, 0.02sec inside the world's qualifying mark.
Griffiths, who finished 11 seconds clear of the field, will be getting up at 4.55 this morning, as usual. She is a postwoman in Cramlington, Co Durham, and thus her daily training consists of lugging a 20-kilo bag around for four hours a morning.
Griffiths, now 24, revived a promising school career six years ago by taking part in the national Post Office Championships. She won those and the European Championships which followed, and her times have been moving down steadily ever since. Yesterday she stamped her mark on the event at international level.