Sagan was the stage winner on Saturday in Krakow. Combined with second place on Monday in the summit finish in Szczyrk, where he regained the lead, and a close third place in Tuesday's sprint into Zabrze, Sagan has garnered invaluable bonus seconds on three of the four stages so far.
After Tuesday's bunch sprint, where he picked up a further four-second time bonus, the reigning world champion is now 10 seconds clear of Dylan Teuns (BMC Racing Team), the stage winner on Monday, with Bora-Hansgrohe teammate Rafal Majka 16 seconds back.
In a week-long stage race with no time trial that is often decided by the bare minimum, even the smallest advantage could prove crucial once the final GC curtain falls on the Tour de Pologne on Friday evening in Bukowina.
"Today [Tuesday] was very hot and the longest stage of the race, 238 kilometres, and the weather conditions affected the conditions a lot," Sagan said afterwards as he and the press sweltered in the interview tents behind the finish line. "It was always flat, but when you got to the finish, you felt tired."
Temperatures mid-afternoon soared to the mid-30s in southern Poland, with race staff watering down the finish area to try and cool down the tarmac. As Sagan pointed out, in a stage lasting nearly six hours, it was hard not to feel drained by the finale, where he was narrowly defeated by two pure sprinters.
"It was not a lot of climbs, almost flat, but I am cooked! We will see what happens tomorrow, but I'm happy to finish this one because it was a very long, hard stage."
"But it's OK, we kept the yellow jersey and we'll see how it's going tomorrow [Wednesday]."
Sagan, in theory, now enters terrain which is more favourable to him. Wednesday's lumpy finale into Rzeszow should enable him to shed at least some of the out-and-out sprinters, and the much shorter stage length, 130 kilometres, will make for a more open race. Then on Thursday, Sagan already knows what it feels like to triumph in Zakopane in the foothills of the Tatras mountains, a stage finish where he was victorious back in 2011 – en route to his overall win.