Come on man, it wasn't a great performance but it was a pre-season friendly.
http://www.dailymail.co.uk/sport/football/article-2183643/Brighton-3-Chelsea-1-Pre-season-friendly-match-report.html
Chelsea finished 3rd that year.
I was just watching a video of Bissouma and it's so impressive the way he keeps the ball in tight spaces and holds off opposing players.
It's even more impressive when you consider that he's only 21.