The British rider finished 11th and 14th on the two stages of the race that were decided in bunch sprints, admitting that he was not in top shape after crashing twice this season.
"It's not been great here to be honest. I messed up on the first two days but I've also had a bit of a lasting problem with my ribs since Mallorca. Then crashing in Omloop Het Nieuwsblad. The first two days here were quite painful but it's been okay since then."
McLay's first fall came in a bizarre turn of events at the Trofeo Palma. He won the race but collided with a photographer just after the line. He was taken to hospital with cuts, bruises and a split lip after a tooth tore through his mouth. The second fall came in Belgium in Het Nieuwsblad, just as he was beginning to find some form.
"The two sprints stages haven't gone quite right but we've done some good work as a team," he said as he searched for a positive take home from Paris-Nice.
"The legs in the sprint aren't that bad it's just not come off for us. Nothing was broken from the crashes. I had an X-ray after Mallorca but it's the intercostal muscles in my chest. I've worked every day with the osteopath with loosening everything up but I'm all closed up at the front. That's not to make an excuse but it's just how it is. It's not panned out here and I'm a little bit disappointed. That's bike racing."
"My tooth went through my lip and I didn't really feel my ribs until a day or two after. I was pretty stiff in neck and spine and it was a big impact. I was just about over it and then crashed again in Het Nieuwsblad."
McLay has battled through a tough edition of Paris-Nice and will be looking to survive the final two mountain stages before heading to his next set of races, which start with the Three Days of Panne later this month.
"Getting through it will make you stronger for the rest of the season. It's also good to get in more races with the guys and get more feeling for the finish. After this I'll have a couple of weeks without a race, and then do De Panne."