I love them both and it feels invidious to have to choose. It's been a privilege to have them both in our team.
Sergio finished his stint with us as the player with
the fewest minutes per goal in PL history, ahead of some genuinely legendary forward players, which is an incredible achievment:
10. Alan Shearer - 147 mins per goal (260 goals in total)
9. Diego Costa - 145 mins per goal (52)
8. Edin Dzeko - 142 mins per goal (50)
7. Robin van Persie - 140 mins per goal (144)
6. Luis Suarez - 139 mins per goal (69)
5. Harry Kane - 128 mins per goal (167)
4. Ruud van Nistelrooy - 128 mins per goal (95)
3. Mo Salah - 127 mins per goal (111)
2. Thierry Henry - 122 mins per goal (175)
1. Sergio Aguero - 108 mins per goal (184)
The above figures are valid as at summer 2021, but neither Kane nor Salah has got close to Aguero in their PL appearances since then.
I don't generally like records that imply that football started in 1992, but it's hard to go back and find exact records of minutes played in the days since substitutes were first allowed in the Football League. However, let's go back and look at a couple of the greatest goalscorers of all time in English football, and keep ourselves to the days before there were substitutes (we can thus be sure of minutes played, as it's 90 minutes for every apopearance).
First, I'll take Jimmy Greaves, because we can be pretty certain that no one has topped his numbers up to the point Aguero was playing. I've taken Greaves's performances in the old First Division from his Chelsea debut in 1957 to the end of the 1964/65 season at Spurs. partly because subs were introduced from the start of the following season and render the calculation less straightforward, and partly because Greaves suffered from hepatitis in the summer of 1965, whereafter his numbers - though spectacular - drop off slightly from before. Thus, I measure what we might call 'peak Greaves'.
The second is Dixie Dean. He scored a total of 349 goals in 399 league appearances for Everton, though one season of that was a Second Division promotion campaign after they were relegated in 1930). We could also note that Dean scored a phenomenal number of goals after the old offside law was changed and the total number of goals scored in the First Division shot up massively as defences were in a degree of chaos. Nonetheless, IMO you can only beat what you're up against.
Anyway, the numbers stack up like this: Dean - 1 goal every 103 minutes (or 1 goal every 105 minutes if his Second Division campaign is disregarded); and 'peak Greaves' - 1 goal every 110 minutes.
So, as a pure goalscorer, Sergio tops anyone from his own era and dating back 30 years from its end, while he's posted numbers that put him up alongside two of the acknowledged greatest goalscorers in English football history. (Yes, we could construct arguments as to why he might most likely be better than that pair, but, for me, comparisons between different eras are rather pointless.)
As I said, it was truly a privilege to have him with us - and for so long, as well. It's now a privilege to have Erling with us, and to witness him breaking all kinds of records. His current ratio is an astonishing 1 goal every 80 minutes in the PL, so he could post some numbers that will never be beaten if he avoids serious injury and stays with us long enough. Let's just hope both of those things happen.