Indian batsman Tanmay Agarwal on Friday smashed the fastest-ever triple century in 147 balls for a first-class cricket record in the country's premier domestic tournament.

The left-handed Agarwal surpassed the previous record held by Marco Marais, a South African batsman who took 191 balls for his 300 for Border against Eastern Province in 2017.

Agarwal, playing for hosts Hyderabad, remained unbeaten on 323 to steer his team to 529-1 in response to Arunachal Pradesh's 172 in a Ranji Trophy group match.

The 701 runs scored on Friday are the second-most in a single day's play in first-class cricket behind the 721 piled up on the first day between Essex and Australians at Southend in 1948.

The touring Australia team had scored all those 721 runs on the first day of that match in 129 overs.

It was records galore as Agarwal also smashed 21 sixes -- the most by a batsman in first-class cricket.

New Zealand's Colin Munro hit 23 during his 281 against Central Districts in 2015.

Agarwal reached the milestone in 183 minutes to be second quickest by time taken behind Denis Compton's 300 in 181 minutes (261 balls) for MCC against North Eastern Transvaal in 1948.