Despite posting a drop of nearly 20% since this time last year, Sugar's 0.2% rise in sales over the past six months was enough to overtake Bliss among teenage readers, with 200,541 sales, compared with Bliss's 151,729, marking the latter's first fall below 200,000.
This time last year, Bliss's average circulation stood at 277,165, but sales slumped 22.7% year on year to 213,466 in the first half of 2006.
This marked a distinct downturn in fortune for Bliss, which had been a solid performer for Emap since its launch in 1985.
Bliss's waning popularity on the news-stand prompted Emap to sell the title last month to Panini, Europe's fourth-largest publisher of youth magazines.
Panini was hoping the acquisition would propel the company to the number one position in the teenage lifestyle sector, but so far the publisher has failed to halt Bliss' downward spiral.
A triumphant Julie Harris, general manager at Hachette, said: "Emap was on a mission to drive Bliss to be number one and they relaunched it a number of times."
She added: "They got to number one, but it wasn't sustainable. The magazine wasn't standing up for itself on the news-stands and teenagers are incredibly fickle and demanding."
Panini's other teen title, Mizz, fared better than its stablemate Bliss, posting only a 0.3% drop between July and December and a 0.8% drop year on year.
Meanwhile, NatMags' Cosmo Girl! managed to maintain its number three spot, despite also suffering a downturn - it lost 7.1% period on period and 23.8% year on year.
But in sharp contrast to the sector as a whole, which was down 24.3% year on year, DC Thomson's Shout magazine and the BBC's Top of the Pops bucked the trend and were both up 8.7% year on year.
Duncan Gray, associate publisher of teen titles at BBC Worldwide, said of Top of the Pops' growth: "It is still a tough market for teen magazines. It has not been easy for the last few periods, but there is demand out there. You just need the right editorial mix."