^ It could have very well made a difference. The OP had some momentum after winning the 2nd set tie-break and the extended delay by the opponent diffused that by cheating. The 6-7 min delay could very well have contributed to some cramping as the OP mentioned.
At my age, the delay could have most certainly made a very significant difference. Because of arthritis in the knees, shoulder issues and tendinitis of the hip (flexor), it takes me quite a while to warm up my body. Once I've got it warmed up, I can keep going for hours. However, any extended breaks will result in joints stiffening up and muscle soreness. If the break is too long, I might as well just pack it up and go home. It is not unusual for me to develop a significant limp after 10 minutes or so after ceasing activity.