Melbourne - Top seed Rafael Nadal said that he needed to be more clinical after dogged fellow left-hander Federico Delbonis frustrated him at the Australian Open on Thursday.
The Spanish world number one created 20 break opportunities but was constantly denied by the Argentine before he wrapped up a 6-3, 7-6 (7/4), 6-1 win on Rod Laver Arena.
The victory set up a third-round clash with countryman Pablo Carreno Busta, his doubles partner at this month's ATP Cup.
"It was a tough match. I lost a lot of opportunities on break point but found a way to finally win the second set," he said. "In the third I was more relaxed, more aggressive and found better play in that set."
Nadal had dropped only 10 games in three previous emphatic wins over 76th-ranked Delbonis and defeat was never on the cards at Melbourne Park.
But the Argentine, whose best Grand Slam result was the third round in Melbourne in 2016, made life hard for the 19-time Grand Slam winner, fending off 17 of his break point chances.
"I think I can do lot of things better. But is not because of Delbonis. I can do things better because of myself. I need to play better," said Nadal.
"Especially I need to convert the break points. But that's just something that happened today. We don't need to put a lot of attention on this.
"Just was something that is hopefully history of just one day."
Nadal looked on track for another straightforward victory after racing through the opening set, sealing it with a trademark crosscourt forehand.
But he found it tougher going in the second, which went with serve up to the tiebreaker.
Nadal, though, came through and Delbonis never recovered as the Spaniard asserted his authority to race home, but not before hitting a ballgirl on the head with a fearsome shot.
He rushed over to console her and gave her a kiss for good measure.
"For her it was not a good moment, I was so scared for her, the ball was quick and straight on her," Nadal said. "I'm very happy she is good. She is brave. Well done."
Victory in Melbourne would make Nadal the first man in the Open era - and only the third in history - to win all four Major titles twice, after Roy Emerson and Rod Laver.
While he has won 12 titles at Roland Garros, four at the US Open and two at Wimbledon, his only triumph in Australia came in 2009 when he beat Roger Federer, with four runner-up finishes to his name.
If he does win a second title in Melbourne, Nadal will equal the 20 Grand Slams crowns held by great rival Federer.
Results on day four of the Australian Open Grand Slam at Melbourne Park on Thursday (x denotes seeding):
Rafael Nadal (ESP x1) bt Federico Del Bonis (ARG) 6-3, 7-6 (7/4), 6-1
Pablo Carreno-Busta (ESP x27) bt Peter Gojowczyk (GER) 6-4, 6-1, 1-6, 6-4
Nick Kyrgios (AUS x23) bt Gilles Simon (FRA) 6-2, 6-4, 4-6, 7-5
Karen Khachanov (RUS x16) bt Mikael Ymer (SWE) 6-2, 2-6, 6-4, 3-6, 7-6 (10/8)
Gael Monfils (FRA x10) bt Ivo Karlovic (CRO) 4-6, 7-6 (10/8), 6-4, 7-5
Ernests Gulbis (LAT) bt Aljaz Bedene (SLO) 7-5, 6-3, 6-2
Taylor Fritz (USA x29) bt Kevin Anderson (RSA) 4-6, 6-7 (5/7), 7-6 (7/4), 6-2, 6-2
Dominic Thiem (AUT x5) bt Alex Bolt (AUS) 6-2, 5-7, 6-7 (5/7), 6-1, 6-2
Daniil Medvedev (RUS x4) bt Pedro Martinez (ESP) 7-5, 6-1, 6-3
Alexei Popyrin (AUS) bt Jaume Munar (ESP) 6-2, 7-6 (7/5), 6-2
John Isner (USA x19) bt Alejandro Tabilo (CHI) 6-4, 6-3, 6-3
Stan Wawrinka (SUI x15) bt Andreas Seppi (ITA) 4-6, 7-5, 6-3, 3-6, 6-4
David Goffin (BEL x11) bt Pierre-Hugues Herbert (FRA) 6-1, 6-4, 4-6, 1-6, 6-3
Andrey Rublev (RUS x17) bt Yuichi Sugita (JPN) 6-2, 6-3, 7-6 (7/5)
Fernando Verdasco (ESP) bt Nikoloz Basilashvili (GEO x26) 4-6, 7-6 (7/5), 6-4, 6-4
Alexander Zverev (GER x7) bt Egor Gerasimov (BLR) 7-6 (7/5), 6-4, 7-5
Belinda Bencic (SUI x6) bt Jelena Ostapenko (LAT) 7-5, 7-5
Anett Kontaveit (EST x28) bt Sara Sorribes (ESP) 6-2, 4-6, 6-1
Donna Vekic (CRO x19) bt Alize Cornet (FRA) 6-4, 6-2
Iga Swiatek (POL) bt Carla Suarez (ESP) 6-3, 7-5
Elise Mertens (BEL x16) bt Heather Watson (GBR) 6-3, 6-0
Catherine Bellis (USA) bt Karolina Muchova (CZE x20) 6-4, 6-4
Yulia Putintseva (KAZ) bt Danielle Collins (USA x26) 6-4, 2-6, 7-5
Simona Halep (ROU x4) bt Harriet Dart (GBR) 6-2, 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
Kiki Bertens (NED x9) bt Arina Rodionova (AUS) 6-3, 7-5
Camila Giorgi (ITA) bt Svetlana Kuznetsova (RUS) 6-3, 6-1
Angelique Kerber (GER x17) bt Priscilla Hon (AUS) 6-3, 6-2
Anastasia Pavlyuchenkova (RUS x30) bt Taylor Townsend (USA) 7-5, 7-6 (7/1)
Karolina Pliskova (CZE x2) bt Laura Siegemund (GER) 6-3, 6-3