For a player who has only been in the league two seasons, New England’s Andrew Farrell has seen a lot. The young right-back for the Revolution, who will play in his first MLS Cup on Sunday, was the No1 draft pick at the start of last year, and went on to play in the Revs’ return to the playoffs in his debut season.

And this year he has already gone further, to an MLS Cup final and a chance to follow up on the series (and personal battle) that ended Thierry Henry’s MLS career, with the chance to spoil another league legend’s last ever game.

Farrell will be facing Landon Donovan at the StubHub Center on Sunday, with the script already set for Donovan to depart on a high having won a record sixth MLS Cup in front of an adoring home crowd. But then again, Farrell and the Revolution have already torn up the script for the final between Henry’s New York and Donovan’s LA, and the young defender, whose exponential improvement in the last two years has mirrored that of the team, is ready to act as a spoiler again.

“I think Charlie Davies [fellow Revs player and former USMNT team-mate of Donovan] was talking about it in a press conference earlier today – he’s such a great player for all of us, for what he’s done for the league, this country and all us American kids coming through, and we still want to end his career with a loss…”

For that to happen, Farrell will be facing the constantly switching front three of the Galaxy attack. He can expect Donovan, newly crowned MLS MVP Robbie Keane, and the player who may have pipped him as No1 draft pick (had he not gone straight into the Galaxy side as a homegrown player) Gyassi Zardes, to be running at him on Sunday afternoon. But the impressively level-headed Farrell is only concentrating on his own aims. “At the start of every season I write down my goals and check them off as they happen,” he says. “So last year, getting drafted by a team, going high in the draft, but now helping my team make the playoffs, win an MLS Cup. And just keep learning from my mistakes and improve.”

At times the learning curve has been steep. It was one of the subtler subplots of the recent New England/New York Conference Final series to watch Farrell go up against Henry, who’d given the then rookie defender a torrid time in a regular season game last year. Towards the end of a still close match, Henry had burst past Farrell on his blindside and left the younger man trailing in his wake as he ran into the box to score. Farrell recalls the moment as “my real introduction to this league”.

He’s not alone. MLS teams tend to economize on salary cap pressures by putting young players at full-back to learn their craft, so the sight of late-period Henry isolating a youngster, or second string player and bullying him with an array of tricks has become a familiar sight in the league. In the Eastern Conference play-in game the luckless victim was Kansas City’s Kevin Ellis, a third-choice defender playing due to injuries to others, who was clearly singled out as a weak link early on by the Frenchman.

And when the Red Bulls were paired against New England again in the MLS playoffs, a lot of the pre-series focus was on how much joy New York could find down the flanks by isolating the full-backs. But while Henry tested Farrell throughout, and managed to spin away to set up a goal in the second leg, he generally found himself up against a much more aware player who more than stood his ground:

“For me he’s one of my favorite players to ever play the game and it’s an honor to go up against him…It’s really hard going against a player of that quality and there was that moment in the first season where he just kind of torched me. And I watched that video over and over again, and it’s obviously at the back of your mind, because you just want to get better. And I understood – it made me get better – because I learnt that you can’t give guys so much space in this league or they’ll punish you.”

“It was fun to play against him though. He’s a great player and will go down as one of the greatest to ever play the game, and I got to play against him a few times …practicing against the best, the more you can learn you get better.”

By the second playoff game against the Red Bulls Farrell was even trying to deceive an unimpressed looking Henry with some feints of his own in the corner (“He’s a big guy and I was stuck with the ball there, so I thought I’d try something … we got a throw in.”), but more generally his interaction with his own fellow defenders and their support from defensive midfielders like Steven Caldwell and Jermaine Jones was showcasing the maturing effectiveness of the Revolution team. I ask him what it was like to come into Jay Heaps’s rebuilding project relatively early:

“Yeah, it’s really felt like a project. He’s brought in a core of young players, good locker room guys, that you can build a team around. I think I am one of those guys, but even before I came they’d done a good job of bringing in guys every year who understood what New England soccer is. Before me they’d brought in AJ [Soares], Chris Tierney, Bobby Shuttleworth. There’ve been a lot of players added in and then in the middle of this year I think adding Jermaine [Jones] pushed us over the edge. It’s been a long time coming together, and I’ve been lucky to become part of it and start well and keep going pretty well.”

As anointed as Farrell’s path might seem his strength is in his humility and his oft-stated willingness to learn. When Zardes was interviewed in the same draft hall where Farrell had shyly taken the stage, he’d promised to “blow your mind” with his skills. Farrell, on the other hand, was happy to quietly leave the hall and catch a flight to New England to continue his education, perhaps crossing another goal off on his list as he did so.

It’s perhaps unfair to set up the two players as diametric opposites, though Robbie Keane pointedly told me in an interview for ESPN last week that “Gyassi’s at the stage in his career where he needs to listen to people,” while Farrell, who I first sat down with in a team meeting room at those Combine trials in Florida, is still the softly spoken, carefully earnest young man, whose personal qualities and willingness to learn were a big part of Heaps being drawn to him.

Farrell will meet Zardes again on Sunday, along with Keane, Donovan et al. Regardless of the outcome, he’ll learn from it dutifully, but when I tell him next time I see him he could be a champion, he indulges in just a little wishful thinking. “That’d be nice. Yeah, I think I’d like that.”

• The Guardian will have minute-by-minute coverage of MLS Cup featuring LA Galaxy vs New England Revolution from 2.30pm ET on Sunday