According to rugby specialists, the young playmaker has demonstrated that he merits the first-choice spot as England's fly-half versus the All Blacks on Saturday.
The Northampton Saints star produced without doubt the best defensive display observed from an England fly-half in several years.
How he fronted up by consistently making defensive hits against an aggressive Fiji side was impressive.
His tactical control was also immense - he demonstrated an excellent balance of finesse and control, while executing some strong decisions during moments were not going as expected in the first half.
His capacity to settle the team tactically and make important decisions represents an aspect he has really nailed.
From my perspective, Fin Smith represents England's number one playmaker and deserves to start versus the All Blacks next week.
I think head coach Steve Borthwick sees it similarly too, since Smith has demonstrated his capability in big Test matches.
George Ford began the previous weekend versus the Wallabies due to captaincy reasons, and part of that choice aimed at ensuring continuity while acknowledging his performance during the visit of Argentina.
But England's showing against Fiji represented a marked step up compared to the display versus the Wallabies.
Australia lost in Italy last weekend, therefore we must not get overly excited about that victory, which should have been by a larger margin given how off the pace Australia performed.
The Fijian team, by contrast, proved significantly threatening while offering a far tougher test.
The young playmaker remains just 23 - projecting forward two years, with Ford pushing him but also offering support, I believe Smith will find himself in an excellent place in his career.
Marcus Smith also has to be regarded as a possibility at the right time and against suitable opponents.
He is developing in his career and is starting to find his feet, though he requires liberty to show his unique qualities.
New Zealand introduced Damian McKenzie, who scored the decisive score to beat the Scottish team, demonstrating the significance of possessing individuals who can make a real impact as substitutes.
That kind of presence can be the difference between winning a World Cup or not.
The All Blacks substitute watches the game unfold from the bench and thinks regarding ways he can make an impact upon entering.
His decision-making and error rate have improved significantly from his initial career.
If we can get Smith to be such type influential player, then having him among substitutes could be beneficial.
However, at the moment I don't think Marcus is the answer at full-back, making it a role remaining up for grabs.
New Zealand will kick to challenge England's defensive line, therefore it must to be impenetrable.
This role requiring transforming into a real strength, in defense and in terms offensive transitions danger.
Right now, I believe Smith functions as full-back in top-tier rugby.
I find it difficult to identify the benefit of playing him there.
I want possession in his hands as much as possible, but I believe that should be in the front line, particularly during the last quarter.
There are obviously a lot of parallels comparing Ford with Smith.
Smith possesses the ability executing right decisions under pressure - his natural reactions are not something that can be taught.
I recall when he got possession at one stage within his own half appearing like it could be on if they swung it wide.
However during these milliseconds he thought they needed to turn Fiji round since England were leading points-wise, so he kicked it to pin the opponents applying pressure.
That's the sort of fly-half play securing titles while claiming global tournaments.
He additionally possesses that calmness under pressure directing the players around him, and the understanding that he mustn't always need to be the first option.
I hope to witness him given the opportunity to show this at elite standards soon, similar to the veteran do, particularly during club level week in consistently.
During the South American tour, the experienced fly-half similarly excelled in difficult circumstances, where historically one might suggest occasions existed he has not quite done so in the very highest-pressure matches.
I believe we have two fly-halves capable of performing the role, though Smith's defence on top of everything else, establishes him as the more complete versatile player.
This also indicates you don't have to modify your defensive system when you have someone aggressive in the fly-half channel, instead of an individual being somewhat passive.
One might present compelling arguments for Ford starting with Smith entering from substitution.
There are so many considerations that go on behind closed doors, but whichever way the coaches decide to go, this will present New Zealand problems.
This hasn't consistently represented the narrative against the All Blacks, where the focus was simply on picking the optimal individual.
On this occasion, either playmaker selected will pressure the All Blacks under real pressure.
Smith's capacity selecting the right kick and execute enabling possible territorial gains might relieve all the stress away from the national team.