Paris Saint-Germain and Real Madrid cancelled each other out at Parc des Princes to ensure top spot in Champions League Group A remains very much up for grabs.
Wednesday's clash between the leaders of Ligue 1 and La Liga - who are both unbeaten in all competitions this season - was billed as a potential pool decider, with the teams locked on six points apiece after two games.
But the stalemate means their reverse meeting at the Santiago Bernabeu in two weeks' time takes on extra importance in deciding who wins the group.
But Madrid reasserted themselves and, after a period of sustained pressure, had tentative appeals for a penalty waved away when Isco went down in the area before Toni Kroos dragged a long-range effort wide.
Jese then forced a smart save from Trapp after latching onto a lovely disguised pass from Kroos, and Ronaldo called the German goalkeeper into action around the half-hour mark with two headers as Madrid turned the screw.
Half-time allowed PSG to regroup, and Edinson Cavani went close soon after the restart with an improvised volley off his studs from Thiago Motta's inch-perfect delivery from the left.
But it was Ronaldo, described by Blanc as a "football alien" in the build-up to the game, who came closest to snatching the elusive opener 20 minutes from time, when he flashed a left-footed shot just wide from Marcelo's pass.
That chance reinvigorated Rafael Benitez's team, but they were unable to penetrate PSG's resolute defence - marshalled superbly by captain Thiago Silva - as the sides were left to settle for a draw.
