I think it should be remembered that these were not standard Russian aircraft. They are in effect Russian airframes matched to some of the best technology in the West, a powerful combination.
Russia has always produced first class airframes, its the electronics that tended to lag behind.
Remember when the Mig 29 first came to notice and it was realised that it was a good amtch to the early F16 but with technology closer to the F4. The helmet mounted sight was more than a bit of a suprise as well.