Though England versus Italy has the potential to be the most gripping -- and finely balanced -- quarterfinal of Euro 2012, there are a few intriguing battles to watch within the maelstrom of 11 versus 11.
As such, some key people to keep in mind during Sunday's action:
Is there any doubt? The entire preamble to the tournament for the Three Lions revolved around strategies to handle his absence. And yet, now that the Manchester United talisman is back and has 90 minutes under his belt, the degree to which he can be effective is crucial if England is to advance. His movement around the attacking third (and back into midfield) can be difficult for defenses to track and he'll need to be extra-sharp if the likes of Ashley Young & Co. are to break down the Azzurri back line.
And his finishing must be sharp; though he did eventually score against Ukraine to give England the Group D top spot, Rooney's early miss on a close-range header showed his rust. Those chances must be converted against this world-class opponent.
The Liverpool right back has been reasonable enough at Euro 2012, but his defensive liabilities have surely caught Italian coach Cesare Prandelli's eye. As such, Johnson's less glamorous responsibilities will fall under extra scrutiny, especially if Andrea Pirlo is capable of finding the Azzurri strikers running free up front. Given that Johnson was arguably culpable in both goals against Sweden, England manager Roy Hodgson will demand prudence from the shakiest link in the back four.
Considering that many griped over the Liverpool captain's inclusion -- let alone receiving the captain's armband -- for the trip to Poland and Ukraine, Euro 2012 has served as a mini-renaissance of sorts for the midfielder. His passing range has been crisp, his vision superb and discipline unsurpassed in the heart of midfield.
But facing a mobile and aggressive bunch in Daniele De Rossi, Thiago Motta and the deep-lying playmaker Pirlo will present a new challenge for England's tigerish leader. Not only will his ability to link up with Rooney and England's wide midfielders be tested -- three assists so far at the Euros illustrates his importance moving upfield -- but also his awareness and positioning to rebuff the Azzurri from controlling too much territory in the attacking third.
Mario Balotelli/Antonio Cassano/Antonio Di Natale
Prandelli is relishing the guessing games as to lineups and formations, given that he's used three different looks and made several switches to get to the quarterfinals. Yet where France manager Laurent Blanc's tinkering looked stressful and needless against Spain, Prandelli's fine-tuning up front has been especially successful. Keeping his three strikers focused and effective has been a breeze thus far, and all three have combined well in various formations. Balotelli's physical presence is a nice fit for Cassano's endless off-the-ball runs and inventiveness, while Di Natale is a classic finisher with plenty of speed to test the defense.
Whichever duo he picks -- assuming he persists with a two-striker set -- will be crucial to the Azzurri's chances.
The 34-year-old Juventus keeper is still at the peak of his powers and will pose a massive challenge for Rooney & Co. to overcome. With 11 saves thus far at Euro 2012 and his safe hands so crucial in preserving valuable points against Spain and Croatia, he must be at his most imperious against the Three Lions.
The summer of wily veterans has been a prevailing motif at Euro 2012, with some turn-back-the-clock brilliance from Andrei Shevchenko, Andrei Arshavin (in flashes) and Antonio Di Natale all memorable. Yet Pirlo would argue that he's always been this strong -- and he's right. Fresh off an undefeated, Scudetto-winning season with Juventus, the midfield maestro has been at his pinpoint best for the Azzurri, sitting deep yet controlling games with his plethora of skills.
England must mark him tightly and not give him room to create, but his ability to find space and dictate the Italians' rhythm will be an essential part of Sunday's quarterfinal. Being surrounded by De Rossi, Motta and Claudio Marchisio does provide enough shelter to pick apart teams with silky passes or bombastic runs; whether he can maintain that influence against an obdurate Three Lions side (I'd expect Scott Parker and at times Rooney to track Pirlo's every more) will be fascinating to watch.
James Tyler is an assistant editor for ESPN.com’s soccer coverage.