"I wouldn't say that I am playing well - I'd give myself a five out of 10 for the Championship so far," said Faletau.
"I am just hanging in there and taking each game as it comes.
"I think there is plenty of room for improvement in my game. I just have to keep working hard on all parts of my game.
"My stats are good but that's nothing big. I don't really bother with them too much - they are not always a fair reflection of how things are going."
Having faced France and Italy in the past two rounds of action, Faletau will finally go head-to-head with another serious Lions contender this weekend as Wales make the trip to Murrayfield to face Scotland.
Montpellier's Johnnie Beattie has been in fine form for the rejuvenated Scots and Faletau expects a hugely physical personal and team encounter in Edinburgh.
"I've had this throughout the tournament - they are all big guys and there have been some great challenges," added Faletau, who is adamant that a possible Championship decider with England and the summer Lions tour to Australia are long way from his focus.
"Louis Picamoles has been outstanding for France. He is lethal with ball in hand and is so hard to stop, and I think Beattie has been the same. He is powerful at carrying and in defence.
"I'm not even thinking about making the Lions tour. The team comes first and it's all about finishing the Six Nations well and getting good results in our last two games.
"All that I am concentrating on is Scotland because you cannot afford to look too far ahead in international rugby, so there's no point in even thinking about England until after this weekend."