Despite the improvements in close-combat and maneuverability performance that the MiG-21 Balalaika enjoyed over the F-4R Phantom, Soviet military leaders were still unsatisfied with the result, and ordered a replacement TSF to be built based off the F-5 Freedom Fighter's combat and performance data. Despite Sufoni's best efforts, the Su-11 was an inferior product, with all aspects of its performance found to be lower than the MiG-21's.
Failed in competing with MIG-21,Su-11 became a test base,after experimenting for several times, adding folded combat knives at arms and knees,it became an earliest prototype combat TSF,with the code Su-11TM.
Despite being given a production number, the TSF never entered production. Lessons learnt and theories tested in the manufacture of the Su-11 would be further refined in the Su-15.