The Irish topped their pool in New Zealand, securing resounding victories over Australia and Italy along the way.
But a tournament that promised so much met an abrupt end when they were put to the sword in the quarter-finals by a Wales side that played with greater accuracy and imagination.
Predicting Ireland's results has proved fiendishly difficult thanks to their fluctuating levels of performance and Best insists only full throttle is now acceptable.
"Going into the World Cup we talked about the need to produce consistency," said the veteran Ulster hooker.
"We had to stop producing big performances when - for want of a better phrase - we felt like it.
"Until that disappointing end against Wales, we proved we can produce big performance after big performance.
"Now the pressure is on us to reproduce that and try to win five games in a row.
"We know that if we can play close to 100%, then there aren't many teams that can live with us.
"The flip side is that in the past we've shown if we don't get it right, there are a lot of teams that can beat us."
Ireland have been installed as joint third favourites to win the Six Nations, alongside England and behind France and Wales.
"There's a fairly short turnaround between games so it doesn't really matter who you play first," said Best.
"It's nice to have a home game up first, but that also adds extra pressure to perform at home.
"It's the start of a new tournament and we're looking forward to that. It's an exciting time if you look at what the provinces are doing."
Ireland enter the match without Keith Earls after the Munster back was withdrawn when his first child, born last week, was admitted into hospital with an unspecified illness.
Fergus McFadden has been promoted to the starting line-up with the uncapped David Kearney, brother of full-back Rob, drafted on to the bench.
"There are moments in your life when you realise there are more important things in your life than rugby," said Best.
"All the players wish him and his family all the best. Hopefully his little girl will get better and Keith will join us soon.
"He's a great character around the squad and will be missed this weekend as a player and a person."
Ireland team: R Kearney (Leinster); T Bowe (Ospreys), F McFadden (Leinster), G D'Arcy (Leinster), A Trimble (Ulster); J Sexton (Leinster), C Murray (Munster); C Healy (Leinster), R Best (Ulster), M Ross (Leinster), D O'Callaghan (Munster), P O'Connell (Munster, capt), S Ferris (Ulster), S O'Brien (Leinster), J Heaslip (Leinster).
Replacements: S Cronin (Leinster), T Court (Ulster), D Ryan (Munster), P O'Mahony (Munster), E Reddan (Leinster), R O'Gara (Munster), D Kearney (Leinster).
Wales team: L Halfpenny (Cardiff Blues); A Cuthbert (Cardiff Blues), J Davies (Scarlets), J Roberts (Cardiff Blues), G North (Scarlets); R Priestland (Scarlets), M Phillips (Bayonne); R Gill (Saracens), H Bennett (Ospreys), A Jones (Ospreys), B Davies (Cardiff Blues), I Evans (Ospreys), R Jones (Ospreys), S Warburton (Cardiff Blues, capt), T Faletau (Newport Gwent Dragons).
Replacements: K Owens (Scarlets), P James (Ospreys), A Powell (Sale Sharks), J Tipuric (Ospreys), L Williams (Cardiff Blues), J Hook (Perpignan), S Williams (Scarlets).
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