My current rank is Nova Master (Nova 4) and I've won 6 games straight. Also was I either 1st or 2nd in my team.
After that, I tied one time, and won 4 games in a row. I still haven't ranked to Master Guardian.
What's keeping me from ranking up? I've been playing with a friend who won 4 (from start of Nova 4 to end) and ranked. Also was he below me most of the times.