"The Six Nations is very much wide open now. It's gone from being fairly bleak (for us) in the first couple of weeks to a very competent performance (against Scotland) at the weekend and some great tries and some great attacking rugby," he said in an interview with BBC Sport.
"It's going to be a massive game against Wales on Saturday week. Win that one and it's wide open going to Twickenham in the last game.
"No doubt the Welsh game is going to be a crunch game. There's a lot at stake and even the battle of the coaches - Eddie (O'Sullivan) and Warren (Gatland) - will be one worth watching too."
Ireland's back-line looked an improved unit against the Scots and while Best believes that Ulster winger Tommy Bowe should enjoy an extended run in the team, he was sitting on the fence with regards to the Geordan Murphy v Girvan Dempsey full-back conundrum.
The former Ulster captain said: "Geordan showed what a class player he is against Scotland. But take nothing away from what Girvan Dempsey has done through the years - he's been one of Ireland's most consistent performers.
"Ireland are extremely lucky that they are able to call on someone like Geordan to step in when Girvan's injured and obviously prove the point on what a class player he is.
"I think it will be a very interesting selection (for the Welsh game) and certainly whichever way it goes, neither player will let him (Eddie O'Sullivan) down.
"It was also great to see Tommy Bowe getting the start that he has so thoroughly deserved through his performances this season for Ulster.
"To score two tries showed what a class act he is and I hope now that's him in the team for some time," he added.
Best was asked during the interview to reflect on one of his fondest memories as an Ireland player - last year's Croke Park win over England during which he came on to replace John Hayes and collect his 14th Test cap.
"Yeah, it was pretty special given the whole significance of the occasion. I'd been to Croke Park a few times watching a couple of football games but to actually be able to play there and to say I'd been part of that occasion was fairly special," Best explained.
"The crowd were just fantastic. I remember coming around the corner just about to go out (onto the pitch) - obviously the lads (in the first fifteen) had gone out just before us.
"The wall of noise was just totally in your face and obviously, through the anthems, it just got louder and louder. A great memory."