I wouldn't have cared one way or the other. If a few minute delay ends my chance at a win, there is something more serious going on with me. I have a hard time defining this as cheating unless you specifically told him that you will cramp up after five minutes of idle time.
Inconsiderate? Maybe. Cheating? Nope. Yeah, I get that there are rulebooks, but tennis is such an uptight sport to begin with. As Steve Winwood once sang, "Roll with it baby."