The championship leader appeared to have stolen a march over his Red Bull rival for most of the Saturday afternoon sprint race at Imola at he sat beyond DRS range and was 1.7s clear.
But the tide began to change on lap 15 of 21 when Verstappen commenced a run of personal best sector times to bring the gap down to 1.1s before dipping under a second to gain DRS.
His first run with the overtaking aid brought him to within 0.5s as Leclerc struggled with front-right graining on his set of red-walled soft Pirelli tyres.
The defending champion then made a pass stick through the Tamburello left-right chicane with two laps remaining.
Leclerc said his ailing tyres were inspired by his attempts early in the sprint contest to build an advantage over Verstappen after nipping past the wheel-spinning RB18 off the line.
He said: “I had a very good start. We weren't side-by-side for Turn 1 and I could focus on my own race from that moment onwards.
“I tried to push at the beginning to get a bit of a gap and for Max to not be in the DRS zone because I knew that I would have been vulnerable if it was the case.
“But I paid the price a little bit later on in the race and had some graining and then really struggled in the last two, three laps.”
As a result, Leclerc reckoned addressing the graining and finding a fix ahead of the full grand prix on Sunday was the main lesson to take from the sprint race.
He added that such a “cure” would place him in contention for the win, rather than relying on the powerful slipstream out of Rivazza and the DRS effect into Tamburello.
Asked by Motorsport.com whether he thought the result could be overturned in the GP, Leclerc said: “I think the pace is quite similar [between Red Bull and Ferrari].
“What made the difference at the end was the graining phase that I went through.
“If we manage to cure that all for tomorrow, I'm pretty sure that we're in the fight for the win. If not, it's going to be a bit more difficult.”
Verstappen had observed that his rival initially had more pace before he “ran out of tyres”, which allowed the Dutch racer to close the gap after initially playing a “waiting game”.
However, Verstappen reckoned the possible use of the medium tyre in the GP, should the forecasted rain not impact play, could change the competitive order.
He said: “Today, it worked out for us to be on this compound.
“Let's see tomorrow. I'm of course happy about today but I know that tomorrow, also other tyre compounds coming into play, it might be a bit different.”
