Thomas Pieters enjoyed an emphatic return to action on Thursday to lead the Celtic Classic, while two players withdrew over coronavirus fears.

French duo Alex Levy and Romain Wattel were unable to compete, with the former becoming the first player on the European Tour to test positive for COVID-19.

But Pieters, who became a father during the coronavirus-enforced suspension and delayed his return a little longer than many other players, was in fine shape as he carded a seven-under-par 64.

A bogey on the second hole might have suggested a hint of unease, but the Belgian finished the front nine one under thanks to a pair of birdies.

He made six more gains after the turn, finishing with back-to-back birdies to edge out early clubhouse leader Toby Tree and Australia's Jake McLeod by one stroke.

Edoardo Molinari and Sebastien Soderberg are two of six players within two strokes of the summit.

-7 Pieters
-6 Tree
-5 E. Molinari
-5 Soderberg
-5 Elvira
-5 Kim
-5 Migliozzi
-5 Warren
-5 Mcleod #CelticClassic #GolfForGood
— The European Tour (@EuropeanTour) August 13, 2020

The day did not get off to the best of starts, however, as it was confirmed Levy had been withdrawn after telling organisers he had contact with someone at home over the weekend who returned a positive result.

He was then re-tested and the result came back positive, which led to compatriot Wattel's precautionary withdrawal due to being a contact of Levy's.

Both Wattel and Levy's caddies were said to have tested negative for COVID-19.