Sagan and Dillier swopped leads and rode in tandem after they broke away with approximately 20km left of the race. They stayed together right until the end, before the world champion took the spoils on the line.
Heading towards the halfway mark of the race, DiData’s Jay Thomson made it in a nine-man breakaway.
The break held their lead for approximately 50km before the chasing bunch caught up at the Trouée d’Arenberg cobbled section with over 90km remaining.
The quartet of Quick-Step Floors’ Zdeněk Štybar and Niki Terpstra, Sagan and EF Education First–Drapac p/b Cannondale’s Sep Vanmarcke made a breakaway from the peloton with just over 50km left.
The quartet were reeled in, before Sagan broke clear and joined the remnants of the day’s early breakaway of Lotto Soudal’s Jelle Wallays, Dillier and UAE Team Emirate’s Sven Baystrom.
Baystrom dropped away, as Sagan, Wallays and Dillier set the pace in the front. Sagan did most of the work to lead the trio. Wallays dropped back, as Sagan and Dillier, by that time, got away.
Hitting the Carrefour de l’Arbre five-star cobbled section, Sagan and Dillier created a one-minute and 15-second lead over the chasing bunch. Terpstra led the chase over Vanmarcke and Trek–Segafredo’s Jasper Stuyven.
Sagan looked to have worn down Dillier with just several kilometres to go, before the Slovakian pulled away on the final lap in the velodrome to beat the Swiss champion milliseconds before the line. Terpstra outlasted the rest of chasers to fill out the podium.
“I am very tired after the race,” Sagan said afterwards, “but I have to admit, I was not involved in any crashes, I never got a flat, I saved energy and then just did one step forward; I attacked. I kept going until the finish.
“I am very happy. I have to say thank you to all my teammates because they did a great job. They kept the group all together from the start. I did my winning move with 50km to go and I’m very happy to come first. It’s an amazing feeling.”
Sagan also won the Gent-Wevelgem a few weeks ago.
View the results here.