Um, no. You'll "master" it when you develop the ability to stop and restart the engine in space. It's a bit more tricky, take maybe a few more years of work, but important if you want to use the engine and high-energy upper stage to put payloads into temporary parking orbit, as NASA does for interplanetary and lunar missions. It also increases the margin of safety for manned missions.
Congrats, India. You are now fifty years behind the U.S., which developed the "Centaur" hydrogen-fueled upper stage in the mid-1960s.