A strong headwind had made for a slow start to the 217-kilometre race, but the peloton split apart when it turned into crosswinds inside the final 90km.
Defending champion Soren Kragh Andersen (Team Sunweb) was the first to lead off the serious attacks, and Wallays went off in pursuit of the Dane on one of the gravel sectors.
Just as Wallays was about to make the bridge to Andersen, the 25-year-old punctured and had to watch as Wallays cruised past him into the race lead with Mavic neutral spares struggled with the wheel change.
Behind the front-runners, it was Groupama-FDJ that were saddled with the majority of the chasing workload for team leader Arnaud Demare. Niki Terpstra (Total Direct Energie) and Oliver Naesen (AG2R La Mondiale) were the other big names in the reduced group but lacked the teammates to help chase Wallays as his advantage stretched out to a minute.
A few flurries threatened to reduce the deficit, but the stop-start nature of the chase played into Wallays' hands and he actually increased his gap to the chase to a minute and 20 seconds with ten kilometres left.
An attack by Terpstra after a race beset by mechanicals was followed by Naesen, but the pair made only limited inroads into Wallays' lead and the Belgian was able to sit up and enjoy his victory in the final metres.
“There is no better way to finish the season," said Wallays. I felt really good the past couple of weeks and I was especially focusing on Paris-Tours, because this race suits me perfectly.
"Winning in such a way is the icing on the cake. The tough first part of the race certainly played into my hands, and I could take advantage of that later in the race. I could ride along in the first echelon quite comfortably and then, I already felt that my legs were good.”
The bold solo move wasn't the intention for the Belgian but he made the best of the situation to secure the memorable win.
“To be honest, I attacked in order to make a first selection but suddenly, I was riding alone at the front," said Wallays. "I thought that a small group would still join me but that didn’t happen. When Andersen punctured, I was completely on my own. On such a course, it is hard to control the race and I realised it would be a battle, man to man.”
Wallays has eight career victories to his name, and doesn't win out of turn, but has made something of a speciality out of Paris-Tours.
"Today was my third victory at Paris-Tours, two at the pros and one as an U23 rider," said Wallays. "To be called ‘Mister Paris-Tours’ makes me really proud. I even heard words like ‘King Paris-Tours’, that is of course a really special feeling.”
