The Italian said he was "sad and disappointed" to drop out, adding that he had started feeling unwell on Monday after a practice week in Monaco.
His four-hour victory also ended a five-match losing streak against the Italian as Medvedev reached his ninth Grand Slam semi-final.
Title rivals Jannik Sinner and Carlos Alcaraz reached the Wimbledon third round on Wednesday as Japanese superstar Naomi Osaka was demolished on her return to Centre Court after a five-year absence.
The Italian is determined to consolidate his position at the top.
Janik Sinner's anticipated rise to world No.1 was officialised on Monday when the ATP released its new rankings, making him the first Italian ever to hold the top spot.
Jannik Sinner said his burgeoning rivalry with Carlos Alcaraz is "exciting" for tennis after losing in five sets to the Spaniard in the French Open semi-finals on Friday.
"I think everybody wants to watch this match," Alcaraz told reporters on Tuesday.
Jannik Sinner took an unexpected path to the world number one ranking on Tuesday after Novak Djokovic's French Open withdrawal but the youngster said it was the culmination of years of hard work and represented a proud moment for Italy.
They are six young Italians dressed as carrots who are at the French Open in a colourful attempt to inspire Sinner to victory.
The Italian said he was "sad and disappointed" to drop out, adding that he had started feeling unwell on Monday after a practice week in Monaco.
His four-hour victory also ended a five-match losing streak against the Italian as Medvedev reached his ninth Grand Slam semi-final.
Title rivals Jannik Sinner and Carlos Alcaraz reached the Wimbledon third round on Wednesday as Japanese superstar Naomi Osaka was demolished on her return to Centre Court after a five-year absence.
The Italian is determined to consolidate his position at the top.
Janik Sinner's anticipated rise to world No.1 was officialised on Monday when the ATP released its new rankings, making him the first Italian ever to hold the top spot.
Jannik Sinner said his burgeoning rivalry with Carlos Alcaraz is "exciting" for tennis after losing in five sets to the Spaniard in the French Open semi-finals on Friday.
"I think everybody wants to watch this match," Alcaraz told reporters on Tuesday.
Jannik Sinner took an unexpected path to the world number one ranking on Tuesday after Novak Djokovic's French Open withdrawal but the youngster said it was the culmination of years of hard work and represented a proud moment for Italy.
They are six young Italians dressed as carrots who are at the French Open in a colourful attempt to inspire Sinner to victory.
The Italian world number two can come within touching distance of the top-ranked Djokovic in the standings should he triumph in Madrid this fortnight and he arrives in the Spanish capital brimming with confidence and carrying an impressive 25-2 win-loss record for the season.