The reigning French champion had finished eighth in Yokohama and recorded the fastest women’s split in the mixed team relay in Nottingham in June.
But this still represented a huge breakthrough for the 21-year-old who dropped out of last year’s race in Hamburg after the swim.
Germany’s Laura Lindemann – who beat Beaugrand to the junior world title in Edmonton in 2014 – held off series leader Katie Zaferes to go one better than her third place in Hamburg last year. Non Stanford and Jodie Stimpson were the best of the Brits in sixth and seventh.
“Last year I had a crash and today it’s Bastille Day and my boyfriend’s birthday, so I’m very happy to win,” Beaugrand said.
Lindemann said: “I didn’t expect to be on the podium after the swim and bike. I had such a bad transition and just ran for my life. I really like to race here with a home crowd.
“Cassandra was amazing. I raced with her as a junior and mostly I won, but now I’m very happy to see her winning a WTS race.”
The women’s race started an hour after the men’s in Hamburg and was again a non-wetsuit swim. It featured a strong British contingent with Vicky Holland, Jessica Learmonth and Georgia Taylor-Brown, joining Stanford and Stimpson.
The series also welcomed back reigning world champion Flora Duffy. The Bermudan won in Hamburg last summer, and had been out with injury since winning her home WTS in April.
Learmonth, the Commonwealth silver medallist behind Duffy, was ranked eleventh having only appeared twice in the WTS this season, but it was no surprise to see the Yorkshire triathlete emerge first from the water with the competition lined out behind.
Duffy and Taylor-Brown were also in close proximity and it was the Bermudan who surged to the front on the bike as a front pack of six formed also including Beaugrand, Vittoria Lopes of Brazil, and the steadily improving Taylor Spivey of the US, who finished seventh in Leeds.
While Duffy so often manages to break away, either solo or in a small group, the rare presence in WTS racing of 2012 Olympic champion Nicola Spirig, combined with the efforts of Australian Ashleigh Gentle and Britain’s Jodie Stimpson, meant the chasing pack cut the lead from 25sec to just 13sec heading into the final bike lap of six.
The field were back together by the time they reached T2 and while Spirig and Stimpson took the lead initially, it was soon Beaugrand who burst with seeming effortless ease to the front and was never threatened as she decimated a world-class field over the run to win by 30secs.
Rounding out the Brits, Taylor-Brown finished 11th, Learmonth 14th and Holland 22nd, as she slipped from second to fourth in the overall standings.
Hamburg WTS: Race result.