Wales number eight Toby Faletau believes he is not playing well and must improve in their Six Nations clash against Scotland at Murrayfield on Saturday.
Newport Gwent Dragon Faletau is tipped as a British and Irish Lions Test pick for the summer tour to Australia.
He faces another contender in Johnnie Beattie at the weekend and said: "I wouldn't say that I am playing well.
"I'd give myself a five out of 10 for the championship so far."
Faletau, 22, has become an integral part of the Welsh effort since making his debut against the Barbarians in June 2011.
He went on to star as Wales reached the 2011 World Cup semi-finals, a tournament in which he had a 100% tackle success rate from 75 attempts.
Tonga-born Faletau, who has now won 24 caps, also played a crucial role in Wales' 2012 Grand Slam.
However, he has delivered a harsh self-assessment on his form this season, adding: "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."
And in Montpellier's Beattie, Faletau sees a player capable of the performance levels to match France's outstanding Louis Picamoles.
"He's [Beattie] a really good player, athletic and dynamic. He carries well, quick and powerful," said Faletau.
"I've had this throughout the tournament - they are all big guys and there have been some great challenges.
"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."
Interim coach Rob Howley's Wales retain hopes of holding on to the Six Nations title, but only England can complete a 2013 Slam while Scotland are also in the running for this term's crown.
Wales went into the tournament having lost seven straight Test matches, and were beaten 30-22 by Ireland on the opening weekend of the tournament.
A Welsh win in Scotland would be their third away victory of this season's tournament and their record fifth in a row on the road in the championship.
That would match the five-match away run compiled by England's World Cup winners from 2002 to 2004. Only France, with six in a row from 2003 to 2005, have done better since the tournament expanded in 2000.