(CNN) -- World No. 3 Novak Djokovic fought off a last-set challenge from Lukasz Kubot of Poland on Monday to earn a spot in the quarterfinals of the Australian Open in Melbourne.
The Serb, No. 3 seed at the season's first Grand Slam, beat Kubot 6-1, 6-2, 7-5. He nailed 11 aces and 37 winners, compared to four aces and 18 winners by Kubot.
He next faces Jo-Wilfried Tsonga or Nicholas Almagro.
"I'm aware the matches will get more difficult throughout this week. So I'm ready for it," he told australianopen.com.
In other play on Monday, Nikolay Davydenko squeezed out a 6-2, 7-5, 4-6, 6-7 (5-7), 6-3 win over Spain's Fernando Verdasco after nearly four hours of play.
Verdasco, the ninth seed, slammed 15 aces, compared to six for Davydenko, the No. 6 seed. But the Spaniard also made 81 unforced errors and 20 double faults compared with 51 and five for the Russian.
Roger Federer takes on Lleyton Hewitt in later play on Monday.