Pupu originally leaked that one. He is generally trust worthy and if you can read Chinese I highly recommend his book series "Sun Set over the KNAPPO". It gives some pretty interesting insights on China's acquisition of the Su-27 as well as the development of the J-10 fighter and evolution of PLAAF's doctrine.
Regarding the intercept of the VNAF fighters I think PLAAF's electronic attack capability helped out a great deal. The USN supposedly crippled the communications network of the entire Nanjing military district during the 1996 Taiwan strait crisis with just a single Prowler. On the other hand it is my personal belief that the J-10s would've done well had China not employed electronic attack due to the superiority of the J-10As, when compared with the Su-30 MKKs, in air to air combat. There was an official leak, back in late 2010, concerning the "shoot-down" of 5 out of 6 Su-30s by J-10s during an exercise. The only Su-30 that escaped was piloted by one of the premier Su-30 pilots in PLAAF (surname Yang).