Matthews too experienced difficulties in 2018, fracturing his left shoulder at Omloop Het Nieuwsblad and suffering sickness including that which saw him exit the Tour de France after the fourth stage.
The form's been there at the WorldTour events - he finished seventh at Milan-San Remo, fifth at La Fleche Wallonne, second at Eschborn Frankfurt and of course, victory on the final stage of the recent Binck Bank Tour.
Here, the Sunweb rider had enough time to look back to Greg van Avermaet (BMC) and Jasper Stuuyven (Trek-Segafred), do a little arm dance, and enjoy his first WorldTour level one-day race victory.
"Wow, I’m super happy with the day I had," the Australian said. "The boys supported me really well throughout the day, and I’m just super happy that I could finish it of for them with a really strong sprint at the end.”
"This is my first win in a classic. I've had wins on each of the grand tours and I won the green jersey on the Tour de France. But I had never won a one-day race at WorldTour level and I'm especially happy it took place in Québec as I love coming here every year.
"That's the thing I thought about when I crossed the line. "I'm the second Australian to win here after Simon Gerrans. He was one of my idols in cycling. It was one of my team's goals today to race here the way he did in 2014 and I was capable to do that. He won't be here next year unfortunately."
An eighth for Haas was a victory of sorts after struggling this season with feeling run down on debut with the Russian team.
Earlier in the 201km race around the streets of Québec, Guy Sagiv (Israel Cycling Academy), Bruno Langlois (Team Canada), Nicolas Dougall (Team Dimension Data), Alexander Cataford (Team Canada) and Robert Britton (Rally Cycling Team) broke clear after just two kilometres.
The quintet quickly built a lead of over six minutes after three laps, halved a lap later and with 50km to go. An Astana-led peloton reduced the advantage further, their pace resulting in just Britton and Langlois left out the front with two laps to go.
Bora-hansgrohe's Peter Kennaugh, another rider experiencing a difficult 2018, soon joined then attacked the pair and came desperately close to victory. He was swept up by the peloton 300m from the line.