England host Ireland on Saturday in a crunch Guinness Six Nations clash at Twickenham.
The rivals will battle to take their respective title bids into the final round of the championship.
Here, the PA news agency picks out some of the key talking points.
Title aspirations on the line
Championship glory remains a realistic possibility for both teams going into what is essentially a knockout semi-final.
The rivals have so far registered two wins and a defeat apiece and will run out in front of around 82,000 fans knowing that the losing side will be eliminated from title contention.
England have dominated Twickenham meetings during the past decade, winning eight of nine. Yet they were last year condemned to a chastening fifth-placed finish on the back of being crushed 32-18 in Dublin by an Irish team that has since taken significant strides forward.
With a tough trip to Paris to come, defeat for the hosts this weekend from what promises to be a tense affair could lead to them once again ending second bottom in the final standings.
Ireland “red-hot favourites”?
Never shy of stirring things up, England coach Eddie Jones has been rattling through his repertoire of pre-match mind games.
The charismatic Australian has labelled Ireland red-hot favourites and the most cohesive team in world rugby, while also questioning their ability to match England’s physicality and declaring that his side do not fear anyone.
Ireland coach Andy Farrell has been reluctant to engage in a battle of wits with his former Saracens boss, regarding the relentless stream of headline-grabbing remarks as both entertaining and unnecessary.
While attempting to burden opponents is a well-rehearsed tactic for Jones, on this occasion bookmakers also consider England to be underdogs, albeit only marginally.
Smith versus Sexton
It is very much master versus apprentice in an intriguing fly-half battle. England’s Marcus Smith was just 10 years old when Ireland counterpart Johnny Sexton made his Test debut.
Smith, with his electric footwork and ability to pick holes, has shone in his maiden Six Nations campaign and leads the individual points table going into round four.
At the other end of the experience spectrum, Sexton is preparing for a likely Twickenham swansong after confirming he will retire following next year’s World Cup, by which time he will be 38.
The 2018 world player of the year – who has won only twice from seven visits to the home of English rugby – is a big fan of 23-year-old Smith, believing his weekend opponent to have “the world at his feet”.
Anxious wait on Itoje
England’s joy at flanker Tom Curry passing concussion protocols and number eight Alex Dombrandt recovering from coronavirus to make the bench has been tempered by doubts about the availability of Maro Itoje.
Among Jones’ many assertions was that his side play with a physicality that Ireland “haven’t seen before”.
Towering second-row Itoje, who became unwell overnight, is key to that and the hosts know they cannot afford to lose a player of his calibre if they are to be victorious.
Cautious optimism was the message from the English camp on Friday afternoon but Wasps lock Joe Launchbury is on standby for his first international start since December 2020 following a serious knee injury.
Away day blues
Since losing their opening two matches of the 2021 Six Nations, in-form Ireland have won 10 of 11 matches, with a narrow round-two defeat in France the only blot on that record.
Farrell’s developing side have won plenty of plaudits for their expansive style of play, particularly since the autumn, which included a stunning victory over the All Blacks. Yet almost all of their dominant displays have come in Dublin.
Matches on the road have proved to be a far trickier proposition and the Irish are still awaiting their first major away scalp of the Farrell era.
Seldom do visiting teams triumph at Twickenham and the Englishman – who has lost five of seven Tests away from the Aviva Stadium, with victories in Italy and Scotland the exceptions – has urged his players to scale new heights in London.