Piatov started his career in Kirovohrad playing for amateur club Artemida in the 2000Amateur League when he was still was 15 years old. In 2001 Pyatov moved to Poltava where he at first joined Vorskla Poltava junior teams and its second team in lower leagues. In Poltava he spent 5 seasons. His debut at professional level Pyatov made for Vorskla-2 during the 2000–01 season in away game against FC Elektron Romny on 25 March 2001 in Romny, which Vorskla-2 lost 1:3. His debut in the Vyshcha Liha for Vorskla main team Pyatov made at the end of the 2002–03 on 18 June 2003 when Vorskla was hosting FC Illichivets Mariupol and finished the game at draw 1:1. He was bought by Shakhtar from Vorskla for approximately £880,000 on 13 December 2006. He spent the rest of the 2006–07 seasonon loan at Vorskla Poltava. In the 2007–08 season, Piatov replaced Bohdan Shust as the main goalkeeper of Shakhtar Donetsk, playing in league, cup, and UEFA Champions League matches, keeping two clean sheets. For the 2008–2009 season Pyatov will have serious competition for his No.1 spot as Shakhtar loaned out Bohdan Shust, and signed FC Kharkiv 'keeper Rustam Khudzhamov who is reaching his prime and saved FC Kharkiv from relegation. But after Shakhtars' 2–0 loss to FC Lviv, Pyatov regained his place as the clubs' No.1. In a home Champions League fixture against Barcelona Pyatov made 7 crucial saves as Shakhtar were leading 1–0, until Bojan Krkić sent in a cross which was spilled by Pyatov for Lionel Messi to easily tap in to make it 1–1 in the 85th minute. But things went from bad to worse as another cross was sent in Messi rose and headed home giving Barcelona the win, and ruining Piatov's perfect game. Pyatov has cemented his spot as Shakhtar's No.1 after great performances in the 2008–09 UEFA Cup which saw Shakhtar reach the final, beating fellow Ukrainian giants Dynamo Kyiv in the first ever all Ukrainian semi-final. His appearance in the final was marred as he spilled Naldo's freekick into the net to give Werder Bremen an equaliser but Shakhtar won 2–1 in extra time. On 1 November 2009 vs Chornomorets Odessa Piatov played his 100th game for Shakhtar, and in this game he won the Man of the Match, and is also the 1st time coach ever named a goalkeeper Man of the Match. . In 2015 Piatov broke the record of penalties stopped in European competitions by stopping his fourth penalty, a record previously held by Shovkovsky.
