I believe the best way to try to understand this is Peak Elo Ratings. If you aren’t familiar with Elo Ratings, this is a great article explaining how they are calculated. Here are the peak Elo Ratings for the top 100 players, and the age in which they achieved them.
Peak Elo
Age
Elo
1
Novak Djokovic
28
2629
2
Bjorn Borg
24
2622
3
John McEnroe
26
2583
4
Rafael Nadal
27
2552
5
Roger Federer
25
2550
6
Jimmy Connors
26
2521
7
Ivan Lendl
26
2518
8
Rod Laver
31
2509
9
Andy Murray
29
2500
10
Guillermo Vilas
25
2431
11
Boris Becker
21
2419
12
Pete Sampras
22
2407
13
Ken Rosewall
33
2388
14
Stan Smith
26
2381
15
Andre Agassi
25
2376
16
Mats Wilander
24
2371
17
Stefan Edberg
24
2370
18
Ilie Nastase
30
2363
19
Tony Roche
23
2355
20
Arthur Ashe
32
2354
21
David Ferrer
30
2348
22
Vitas Gerulaitis
24
2335
23
Juan Martin Del Potro
20
2331
24
Jim Courier
21
2330
25
John Newcombe
27
2327
26
Brian Gottfried
25
2324
27
Tom Okker
30
2317
28
Daniil Medvedev
25
2316
29
Gene Mayer
24
2303
30
Alexander Zverev
24
2303
31
Jose Luis Clerc
22
2297
32
Kei Nishikori
26
2296
33
Lleyton Hewitt
21
2295
34
Nikolay Davydenko
28
2291
35
Stan Wawrinka
29
2291
36
Manuel Orantes
26
2290
37
Thomas Muster
28
2287
38
Eddie Dibbs
27
2282
39
Gustavo Kuerten
24
2281
40
Andy Roddick
21
2274
41
Michael Stich
25
2272
42
Robin Soderling
26
2271
43
Milos Raonic
25
2269
44
Yannick Noah
23
2268
45
Michael Chang
24
2267
46
Tomas Berdych
29
2263
47
Andres Gimeno
31
2261
48
Roscoe Tanner
27
2261
49
Stefanos Tsitsipas
22
2258
50
Miloslav Mecir
23
2257
51
Harold Solomon
27
2256
52
Patrick Rafter
25
2255
53
Dominic Thiem
27
2250
54
Raul Ramirez
23
2249
55
Goran Ivanisevic
21
2246
56
Jo Wilfried Tsonga
26
2244
57
Dennis Ralston
25
2242
58
Joakim Nystrom
23
2242
59
Adriano Panatta
25
2241
60
Marcelo Rios
22
2241
61
Sergi Bruguera
23
2232
62
Marin Cilic
25
2232
63
Guillermo Coria
22
2229
64
Cliff Drysdale
30
2227
65
Andrey Rublev
23
2227
66
Earl Butch Buchholz
27
2226
67
Roy Emerson
31
2225
68
Juan Carlos Ferrero
23
2225
69
Carlos Alcaraz Garfia
19
2225
70
Marty Riessen
30
2223
71
Andres Gomez
25
2223
72
Petr Korda
30
2222
73
Marat Safin
25
2218
74
Pat Cash
22
2217
75
Yevgeny Kafelnikov
25
2216
76
Richard Krajicek
27
2214
77
Kent Carlsson
20
2213
78
Cliff Richey
23
2212
79
Dick Stockton
26
2212
80
Jose Higueras
26
2210
81
Brad Gilbert
28
2210
82
Fernando Gonzalez
26
2209
83
Alex Metreveli
29
2208
84
Ivan Ljubicic
27
2206
85
Fernando Verdasco
26
2204
86
Richard Pancho Gonzales
42
2203
87
Grigor Dimitrov
26
2203
88
Eliot Teltscher
22
2200
89
Jan Kodes
27
2197
90
David Nalbandian
28
2196
91
Richard Gasquet
29
2196
92
Carlos Moya
27
2190
93
Tommy Haas
23
2189
94
Gael Monfils
30
2189
95
Magnus Larsson
25
2188
96
Todd Martin
28
2188
97
Henri Leconte
23
2187
98
Jakob Hlasek
24
2184
99
Anders Jarryd
24
2182
100
Alex Corretja
26
2182
There are a few outliers I think that we need to remove in the mix here.
8
Rod Laver
31
2509
47
Andres Gimeno
31
2261
67
Roy Emerson
31
2225
20
Arthur Ashe
32
2354
13
Ken Rosewall
33
2388
86
Richard Pancho Gonzales
42
2203
These were all players that didn’t have the benefit of playing in the Open Era until they were in their 30’s. I don’t think we can include them when there is no record of how good they were in their 20’s. Likely better players had the system been in place to allow them to compete like they did in the Open Era.
For a very different reason, Carlos Alcaraz needs to come off the list as well. He has many more years ahead of him and will likely post many higher Ratings than he has.
69
Carlos Alcaraz Garfia
19
2225
While it is certainly possible, these players have peaked, especially Thiem coming off of injury. I do believe it’s too soon to count any of them as having ultimately peaked just yet.
65
Andrey Rublev
23
2227
49
Stefanos Tsitsipas
22
2258
30
Alexander Zverev
24
2303
28
Daniil Medvedev
25
2316
53
Dominic Thiem
27
2250
Removing those 12 from the All Time Top 100, the average peak age of the remaining is