Quick Step had also featured in the day's primary breakaway, with Van Keirsbulck part of the leading group on the road for all but the last 20 km (12 mi).
Despite Boonen's intentions of hindering the chase, the break was caught, with Team Sky's Ian Stannard the last man brought back.
Steegmans began performing a leadout when Stannard was caught, and Boonen reacted essentially on instinct to sprint for the win.
He and Filippo Pozzato tried to follow Fabian Cancellara's accelerations on the Leberg, the day's fourteenth cobbled climb, but soon found themselves gapped off.
He was able to stay with the front of the race when Cancellara, Philippe Gilbert, Alessandro Ballan, and Bjorn Leukemans formed the day's final selection.
Cancellara put in a second acceleration on the Bosberg, the eighteenth and final cobbled climb on the day's profile, and only Chavanel and Nick Nuyens could follow.
Boonen had his chain slip and get stuck between the frame and crankset of his bicycle, a problem which required a full bike change.
At that point, he crashed with former teammate Maarten Wynants and landed on his knees, sustaining such an injury that he was unable to continue in the race.
Chavanel, for his part, flatted twice, both at moments when his group was racing at a high speed, meaning it was hard for him to chase back on.
While he and Andrey Amador rode the stage's final kilometers in an unstrategic fashion, allowing the chase pack to catch them,[38] Malacarne's efforts did not go unrewarded.
Despite very limited road experience, Štybar showed quite well, coming third on the race's hardest stage[40] and finishing in that same position on the final podium.