The double Olympic medallist was in superb defensive form throughout the day here, and took gold with a narrow 2-1 win over two-time world champion Heiki Nabi of Estonia.

It was billed as a titanic clash between two of the most successful Greco-Roman wrestlers but it failed to live up to expectations as points were only awarded for passivity or step-outs.

But it still provided a fascinating conclusion to the Greco-Roman programme at these Championships, with the next four days taken up by competition in women's and men's freestyle.

Armenia and Turkey both sealed their second gold medals of the event, while the other crowns on offer on day two went the way of Japan's Kenichiro Fumita and Ryu Han-su of South Korea.

Kayaalp, the top seed, was tipped as the pre-event favourite and was able to battle through the early rounds without too much difficulty.

The 27-year-old, whose previous world titles came on home soil in Istanbul in 2011 and in Las Vegas two years ago, knew he would face a much sterner test in the final.

Nabi's first world crown came in the 98kg competition at the 2006 Championships and the 32-year-old Olympic silver medallist rolled back the years during the early stages with a series of vintage, if not particularly entertaining, performances.

The final proved a step too far for the Estonian, however, as he was forced to settle for silver following an agonising defeat.

Yasmani Acosta Fernandez made history as the first Chilean wrestler to win a medal at a World Championships in any category and in any discipline as he claimed bronze by beating Ukraine's Mykola Kuchmii 2-0.

Pan American champion Oscar Pino Hinds of Cuba joined Fernandez on the podium with a 3-1 victory over Kiryl Hryshchanka of Belarus.

South Korea's Ryu Han-su, the 2013 world champion, banished the disappointment of finishing second in Las Vegas in 2015 as he topped the podium in the 66kg tournament.

The 29-year-old Asian Games gold medallist edged Mateusz Bernatek of Poland in the final.

Atakan Yuksel of Turkey and top-seeded Russian Artem Surkov, the reigning European champion, clinched the two bronze medals with victories against Iran's Mohammad Elyasi and Karen Aslanyan of Armenia respectively.

Japan's Fumita took the 59kg honours as he overcame Mirambek Ainagulov of Kazakhstan 2-1 to become his country's first Greco-Roman world champion in 34 years.

Not since Masaki Eto won the 57kg category at the 1983 World Championships in Kyiv had Japan triumphed in Greco-Roman but Fumita set that record straight today.

The 21-year-old beat Ainagulov in the Asian Championships final in New Delhi earlier this year and again had the better of the Kazakh to secure the world title.

Maksim Manukyan, the fourth seed in the 80kg competition, delivered Armenia's second gold of the event here with a comfortable 5-0 success aginst Radzik Kuliyeu of Belarus.

It marked the Armenian's first major international medal - and he did it in style as he produced three quick scoring throws to take down his Belarusian opponent.

Germany's Pascal Eisele, the third seed, beat European champion Zurab Datunashvili of Georgia by fall in the opening bronze medal bout.

Azerbaijan's Elvin Mursaliyev, who stunned two-time Olympic champion Roman Vlasov of Russia in the preliminary stages, took the other bronze on offer in the 80kg weight division by defeating Bulgarian Daniel Aleksandrov.

Russia earned the team Greco-Roman crown on 46 points ahead of Iran and Turkey, silver and bronze medallists respectively.

Turkey finished day two at the summit of the medals table with two golds and a bronze.

Armenia are second on two golds and Germany are third having won a medal of each colour so far.