Ireland pulled off the calendar-year clean sweep over the southern hemisphere's big three in a hugely-impressive autumn series.
Here, Press Association Sport examines five key lessons from the November Test run.
1. Ireland and England are the front-runners for RBS 6 Nations glory
Ireland backed up their June win over South Africa with victories over New Zealand and Australia this month. Joe Schmidt's side are the first European Test team to beat the southern hemisphere trio in a calendar year since England in 2003. Ireland now sit fourth in the world rankings, but with a stellar Six Nations might even overhaul the Wallabies into third. England remain second in the world standings behind New Zealand. All this points to a potentially monumental Six Nations closer between Ireland and England in Dublin on March 18. By that point England could even be scenting a record 19th consecutive win. Should Ireland also remain unbeaten in the tournament and the match become a grand slam decider, Dublin could play host to one of the Six Nations' most dramatic finishes yet.
2. Tadhg Furlong emerges as a genuine British and Irish Lions prospect
Tighthead prop Furlong revealed he felt "embarrassed" to be linked to the Lions after Ireland's 27-24 win over Australia in Dublin on Saturday. But the 24-year-old has not just nailed down Ireland's number-three shirt this autumn - he has also laid down a massive Lions marker. The Wexford native surely sits ahead of Wales' Samson Lee, England's Dan Cole and Scotland's WP Nel at this point in proceedings. Flourish in the Six Nations and Furlong will definitely be on the plane to New Zealand next summer.
3. Garry Ringrose is the real deal
Leinster's young centre Ringrose finally came of Test-match age this autumn, offering graft and robustness to add to his line-breaking abilities. The 21-year-old was forced to operate out of position at inside centre against Australia, but acquitted himself extremely well under duress. His game-breaking abilities offer boss Joe Schmidt a serious alternative to defensive captain Jared Payne at outside centre.
4. New Zealand still lead the pack, but are human after all
Most neutral observers ended October pondering whether Steve Hansen's All Blacks could be rugby's greatest team of all-time. But then Ireland ended their record 18-match winning streak with the historic 40-29 victory in Chicago on November 5. The All Blacks recovered some poise with their 21-9 win over Ireland in Dublin two weeks later, but will have left Europe fairly frustrated with their overall tour performance. The All Blacks remain the world's best team, but Ireland have proved they can be toppled. England for one will have watched on with encouragement at that Soldier Field triumph.
5. Disciplinary chiefs must keep clamping down on dangerous play
Governing body World Rugby has issued a number of crackdowns on dangerous and head-high tackles this month. The first seemed to go unheeded, if New Zealand's hits in Dublin against Ireland were anything to go by. The fall-out from Jaco Peyper's officiating in that 21-9 defeat left disciplinary chiefs admitting the South African referee ought to have sent off Malakai Fekitoa, rather than issue a yellow card. The mere penalty for Sam Cane's head-clattering shoulder hit that left Robbie Henshaw concussed was ruled as the right punishment. But one week on World Rugby were again issuing mandates reminding players to focus on safety. Australia's Dean Mumm was perhaps fortunate to avoid a red card for dumping Furlong on his head in the Wallabies' defeat to Ireland. But a yellow card there at least again reiterated the general mood to force players to take greater care of each other in battle.