Australian Open: Rafael Nadal battles into final in Melbourne, chasing record 21st grand slam

• Spaniard fights Matteo Berrettini in four sets 6-3, 6-2, 3-6, 6-3 to keep historic title in his sights
• Daniil Medvedev and Stefanos Tsitsipas are up next on Rod Laver Arena in second semi-final