Melbourne - Fourth seed Daniil Medvedev overcame a nosebleed and stiff resistance from Spanish qualifier Pedro Martinez on Thursday to book his Australian Open third round ticket.
The Russian was pressed hard in a competitive first set before grinding down the 22-year-old 7-5, 6-1, 6-3 with the roof closed on Margaret Court Arena.
"It was not easy, especially the first set but I managed to stay there the whole match and came through because he has less experience," said Medvedev, who won four titles last year and was runner-up at the US Open.
"I tried to push him all the time and that worked well today. Today was much better than my first match."
The highest seed behind the Big Three of Rafael Nadal, Novak Djokovic and Roger Federer, Medvedev struggled to get going against a tenacious player making his Australian Open debut.
But his strength and big serve ultimately counted, with 19 aces.
The pair stayed on serve until the Russian's pressure paid dividends in the first set, working break points in game four and getting the edge when Martinez, ranked 168, sent a backhand into the net.
But poor technique on a volley handed the Spaniard a break back for 3-4 and Martinez's confidence grew.
They went game for game until Medvedev stepped up a gear to break again for the set when Martinez put a simple forehand into the net.
With the Spaniard sapped of energy, Medvedev twisted the knife, racing into a 5-0 second set lead before his nose started dripping blood and he needed a medical timeout.
He returned to wrap up the set. But Martinez refused to give up and put up a battle that belied his ranking to ensure the world number four had a testing workout.
Medvedev, 23, is aiming to better his best performance at Melbourne Park which came last year, when he made the round of 16 before falling to eventual champion Djokovic.
His reward for beating Martinez is a clash against either Australian Alexei Popyrin or Spain's Jaume Munar.
Results on day four of the Australian Open Grand Slam at Melbourne Park on Thursday (x denotes seeding):
Daniil Medvedev (RUS x4) bt Pedro Martinez (ESP) 7-5, 6-1, 6-3
Belinda Bencic (SUI x6) bt Jelena Ostapenko (LAT) 7-5, 7-5
Donna Vekic (CRO x19) bt Alize Cornet (FRA) 6-4, 6-2
Catherine Bellis (USA) bt Karolina Muchova (CZE x20) 6-4, 6-4
Garbine Muguruza (ESP) bt Ajla Tomljanovic (AUS) 6-3, 3-6, 6-3
Zarina Diyas (KAZ) bt Anna Blinkova (RUS) 4-6, 6-3, 6-4
Karolina Pliskova (CZE x2) bt Laura Siegemund (GER) 6-3, 6-3