The triple world champion has built a special relationship with the seven-stage North American World Tour race, which has a knack for bringing out the best in him.
Not only has the Bora-Hansgrohe superstar amassed 16 stage victories since his debut in 2010, he has also won the green jersey on a record seven occasions between then and 2017.
During that stretch of dominance, he only missed out on green in 2015 when he had bigger fish – in the shape of Julian Alaphilippe’s yellow jersey – to fry.
That year, the Slovenian was able to limit his losses to the Frenchman on Mount Baldy – a climb that will reappear on stage six of this year’s race – to set him up for a bonus seconds coup of the GC on the final day.
A well-timed intermediate sprint brought him to within one second of Alaphilippe and third on the stage was enough to overthrow his opponent and put him in the final yellow jersey by three seconds.
Although the defeated youngster would return to win the tour the following year to start a steady march to the very top of the pro peloton, a buoyed Sagan went on to bag the first of his world titles in Richmond in the United States later that year.
Apart from scalps in hard-man races such as Gent-Wevelgem, the 2016 season would yield his first Monument victory at the Tour of Flanders. He mugged Sep Vanmarcke on the Paterberg and, despite the Belgian teaming up with Fabian Cancellara in chase, soloed the last 14km home in that familiar straight-back style of his.
The nature of that victory pretty much propelled him to number one favourite in all subsequent cobbled classics and other similarly tough races that he would enter over the next few seasons.
Even though his second Monument victory only came at last year’s Paris-Roubaix, it is probably fair to say that his peers acknowledged him as the general of the peloton during that time.
In many respects, the 2015 Tour of California signalled the start of a golden era in Sagan’s career which, let’s not forget, also includes a record-equalling six – should’ve been seven – green jerseys in the Tour de France.
Such has been his superiority, that it is easy to forget he headed to California that year after a particularly lacklustre spring campaign, which saw him capitulate in both E3 Harelbeke and Tour of Flanders when in with a shout of victory.
The 2019 season has had an eerily similar feel, with the 29-year-old seemingly running out of fight within sight of the finish while in contention in several classics.
The defence of his title at Paris-Roubaix, where he was on the attack the one moment and out the back the next, is a case in point.
As much as he tried to find his form in the Ardennes classics in the aftermath, Sagan evidently had nothing more to give and eventually took leave from the peloton without making his much-anticipated debut at Liege-Bastogne-Liege.
It takes a big man to acknowledge that you are beaten – even if it is just briefly – and tapping out was, for him and his legion of supporters, perhaps the least painful scenario.
As he did four seasons earlier, he went on “holiday” to do whatever it is that Peter Sagan does when he needs time out, but not before making sure that his ticket to the Tour of California was booked.
History might just repeat itself.