No. 1 Broad defers to top two
Broad - the first England bowler to reach No. 1 in the rankings since Steve Harmison in 2004 - believes that Dale Steyn is "the bowler of our generation" and that James Anderson is "the best bowler England have ever had". Steyn is currently placed at No. 3 in the Test rankings, with Anderson at No. 5.
But Broad's spell in Johannesburg did reiterate the point that, given any help from the conditions, he can be devastating. With his sustained fitness - for which he credits the England support staff - appearing to help him contribute such spells more often, he has formed a potent partnership with Anderson. It bodes well for England that both are in the top five.
"I'm not going to walk away from this week thinking I'm a better bowler than Dale Steyn or Jimmy Anderson because that is not the case," Broad said. "But it is a nice feeling to have reached this mark through my performances.
"It is not something to take for granted and it is a very special thing to have happened. When you consider that only Ian Botham in the 1980s and Harmy in 2004 have been No. 1 as English bowlers, it is a lovely achievement.
"The biggest thing is that I've stayed fit. You can't take wickets on the physio bed can you? So a lot of credit has to go to the guys behind the scenes for keeping me fit and I also understand my body a bit more now. I've played nearly 40 Tests on the bounce now which is quite rare for a fast bowler.
"It might sound odd, but I'm not the best bowler in the world. Dale Steyn is the bowler of our generation. Just have a look at his record: his wickets; his strike rate; his average. He is the best bowler in the world.
"My dad always talks about Malcolm Marshall being the bowler of his generation. Well, Dale Steyn is the bowler of our generation.
"I've been very privileged to play with Jimmy Anderson for a long time and he is certainly the best bowler England have ever had in my view. I didn't see Fred Trueman and didn't watch much of Ian Botham live, so you have to judge it on who you've seen bowl."
While Broad is flattered by the "very special" achievement, he sees it not as an end in itself but as a marker on England's road of progress. Whatever happens in Centurion, they will rise no higher than No. 5 in the rankings at the end of this series. The aim, clearly, is to reach No. 1 but with a desperately tough series looming in India at the end of the year, Broad knows that ambition is still some way off fulfilment.
"This is not the end goal and it doesn't feel like the biggest thing right now because there is so much more going on with the team," he said. "I'm not being aloof or disrespectful, but there is such a determination in the side to get this team to No. 1.
"In saying that, when Trevor took over he did say that the only way to get the team to No. 1 is for individual players to start climbing the rankings. And we've had Rooty at No. 1 as a batsman, Jimmy and I have consistently been in the top five or six for a while and Stokesy is climbing high in the allrounders.
"There is such a goal for this team to become the best, and we know it is still a way off just now, but give this team another year's experience and then it really becomes an exciting time."
It may well not be a coincidence that Broad has risen through the rankings since he was dropped from England's white-ball teams. By the end of the 2014 England season, he was rated No. 8 in the world but, after a disappointing World Cup early in 2015, he was dropped from the limited-overs squads and as, as a consequence, has played red-ball cricket almost exclusively. As well as potentially helping with his fitness, that decision has enabled him to concentrate on maintaining the fuller length that has been a key ingredient in his improvement.
He retains hopes, however, of winning back his place in both the ODI and T20 sides and has ambitions to play in the 2019 World Cup in England. Indeed, he had thought that, with Steven Finn out of the rest of this tour, it was possible he could return to the limited-overs squad as his replacement; Liam Plunkett was called up instead.
"I'm desperate to play white-ball cricket again for England," he said. "You have a short career and I'm not going to play until I'm 37 or 38, so I want to play as much cricket as I possibly can.
"My consistency has got better with the red ball probably through playing more exclusively red-ball cricket. But I don't think the fitness thing is a direct correlation because I've taken the most Test wickets since 2011 and I've played white ball cricket through that, but I am as fit as I've ever been now.
"I'm as fresh as I've ever been, the knee surgery was the best decision I've ever made, and I'm loving my cricket.
"Yes, I do want to play in the ODIs. Absolutely. I haven't had any conversations about it. I'm happy for the selectors to do their thing, but I'll probably speak about it at some point.
"There is a lot of important white-ball cricket coming England's way with the World T20, the Champions Trophy and then the 2019 World Cup. I want to be involved.
"The dream of mine is to play in that World Cup and win it at home. That would be epic.
"It is still a long way away, but playing ODIs in England is important for that. I'm just looking to improve and I know I can make improvements in white-ball cricket, but I can also change games if given the chance."
George Dobell is a senior correspondent at ESPNcricinfo