The 23-year-old Italian, who rides for Bardiani-CSF-Faizanè, finished outside the time limit on the 15.1km downhill time trial, coming in more than seven minutes down on Ganna's best time of 15-24.
Covili suffered persistent mechanical issues, forcing him into two bike changes, which never allowed him to properly engage with the race against the clock on a course that saw riders clocking speeds of over 100km/h. The young Italian now leaves his home Grand Tour after racing just 15km.
The next slowest rider to finish was Androni Giocattoli-Sidermec's Luca Chirico, who finished exactly four minutes down on Ganna but crucially inside the time limit, which was around 4-45.
This was Covili's second Giro d'Italia, having finished 84th overall at the 2019 Italian Grand Tour, where the evidence points towards him not being a time trial specialist, having finished outside the top 100 places in all three of that edition's TTs.
This is the second year in a row a rider has finished outside the time limit of the opening Giro d'Italia time trial.
Nippo Vini Fantini Faizanè's Hiroki Nishimura finished 4-36 down on Primož Roglič (Jumbo-Visma) on the 8.2km opening time trial of the 2019 Italian Grand Tour, with the time cut off being 3-52. The course featured a 2km uphill ramp to the Madonna di San Luca, compared with the downhill offering that opened the 2020 race.
The then 24-year-old Japanese rider blamed a bad night's sleep for his performance, saying he was nervous before the start of his first-ever Grand Tour stage.
174 riders will start stage two after Miguel Ángel López abandoned, the Colombian involved in a bizarre crash at the second time check and being taken to hospital in an ambulance. The Astana man luckily didn't break anything but suffered a deep wound very close to the iliac artery.
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