Melbourne - Grigor Dimitrov said things were on the "right path" with new coach Andre Agassi in his corner after recovering from a slow start to beat Janko Tipsarevic in the Australian Open on Monday.
The 27-year-old Bulgarian, nicknamed "Baby Fed" for his one-handed backhand reminiscent of Roger Federer, won 4-6, 6-3, 6-1, 6-4 watched by the American great on 1573 Arena.
"I have known Andre for a really long time, since I was 14," said Dimitrov, who reached the semi-finals at Melbourne Park two years ago and a career-high ranking of three the same year.
"We just wanted to kind of add a person that has done a little bit of, I mean, of what we are trying to achieve.
Dimitrov, who has tumbled down the rankings to 21st, called Agassi, who won eight Grand Slams with four of them coming at the Australian Open, one person that "I could trust unconditionally".
"Step by step, we developed our relationship and next thing you know he's in here watching my first match," he said.
"On a daily basis, I have learned something new from him. He's super intense on the court. We are all like on the same page. That's really important.
"But, I mean, the biggest thing that stands out is that I'm learning something every single day. So I think things are going on the right path for me."
Dimitrov next faces unseeded Uruguayan clay court specialist Pablo Cuevas for a place in the last 32.
Results from Day 1 of the Australian Open on Monday:
Men
Round 1
Radu Albot (MDA) bt Michael Mmoh (USA) 3-6, 6-3, 6-4, 6-2
Fernando Verdasco (ESP x26) bt Miomir Kecmanovic (SRB) 7-6 (7/5), 6-3, 6-3
Karen Khachanov (RUS x10) bt Peter Gojowczyk (GER) 3-6, 6-3, 6-4, 6-3
Stefanos Tsitsipas (GRE x14) bt Matteo Berrettini (ITA) 6-7 (3/7), 6-4, 6-3, 7-6 (7/4)
Stefano Travaglia (ITA) bt Guido Andreozzi (ARG) 6-7 (3/7), 6-2, 6-3, 6-2
Nikoloz Basilashvili (GEO x19) bt Christopher Eubanks (USA) 6-4, 4-6, 7-6 (8/6), 6-3
Daniel Evans (GBR) bt Tatsuma Ito (JPN) 7-5, 6-1, 7-6 (10/8)
Kevin Anderson (RSA x5) bt Adrian Mannarino (FRA) 6-3, 5-7, 6-2, 6-1
Frances Tiafoe (USA) bt Prajnesh Gunneswaran (IND) 7-6 (9/7), 6-3, 6-3
Grigor Dimitrov (BUL x20) bt Janko Tipsarevic (SRB) 4-6, 6-3, 6-1, 6-4
Pablo Cuevas (URU) bt Dusan Lajovic (SRB) 6-4, 7-5, 6-1
Thomas Fabbiano (ITA) bt Jason Kubler (AUS) 6-4, 7-6 (7/1), 2-6, 6-3
Reilly Opelka (USA) bt John Isner (USA x9) 7-6 (7/4), 7-6 (8/6), 6-7 (4/7), 7-6 (7/5)
Robin Haase (NED) bt Guillermo Garcia-Lopez (ESP) 7-5, 6-4, 7-5
Diego Schwartzman (ARG x18) bt Rudolf Molleker (GER) 6-1, 6-3, 4-6, 6-0
Alex De Minaur (AUS x27) bt Pedro Sousa (POR) 6-4, 7-5, 6-4
Rafael Nadal (ESP x2) bt James Duckworth (AUS) 6-4, 6-3, 7-5
Women
Round 1
Yulia Putintseva (KAZ) bt Barbora Zahlavova Strycova (CZE x32) 6-4, 7-6 (7/1)
Lesya Tsurenko (UKR x24) bt Ekaterina Alexandrova (RUS) 6-4, 7-6 (7/4)
Amanda Anisimova (USA) bt Monica Niculescu (ROM) 7-6 (7/3), 6-4
Katie Boulter (GBR) bt Ekaterina Makarova (RUS) 6-0, 4-6, 7-6 (10/6)
Aryna Sabalenka (BLR x11) bt Anna Kalinskaya (RUS) 6-1, 6-4
Wang Yafan (CHN) bt Ellen Perez (AUS) 6-4, 6-0
Astra Sharma (AUS) bt Priscilla Hon (AUS) 7-5, 4-6, 6-1
Maria Sakkari (GRE) bt Jelena Ostapenko (LAT x22) 6-1, 3-6, 6-2
Maria Sharapova (RUS x30) bt Harriet Dart (GBR) 6-0, 6-0
Rebecca Peterson (SWE) bt Sorana Cirstea (ROU) 6-4, 6-1
Johanna Larsson (SWE) bt Vera Lapko (BLR) 7-6 (7/5), 3-0 retired
Sloane Stephens (USA x5) bt Taylor Townsend (USA) 6-4, 6-2
Tímea Babos (HUN) bt Ons Jabeur (TUN) 7-6 (7/5), 7-6 (7/3)
Marketa Vondrousova (CZE) bt Evgeniya Rodina (RUS) 6-3, 6-2
Petra Martic (CRO x31) bt Heather Watson (GBR) 6-1, 6-2
Anett Kontaveit (EST x20) bt Sara Sorribes (ESP) 6-3, 6-2
Anastasia Pavlyuchenkova (RUS) bt Monica Puig (PUR) 6-4, 6-3
Kiki Bertens (NED x9) bt Alison Riske (USA) 6-3, 6-3
Danielle Collins (USA) bt Julia Georges (GER x14) 2-6, 7-6 (7/5), 6-4
Sachia Vickery (USA) bt Ysaline Bonaventure (BEL) 2-6, 6-4, 6-4
Zoe Hives (AUS) bt Bethanie Mattek-Sands (USA) 6-1, 6-2
Caroline Garcia (FRA x19) bt Jessika Ponchet (FRA) 6-2, 6-3
Donna Vekic (CRO x29) bt Kristina Mladenovic (FRA) 6-2, 6-4
Kimberly Birrell (AUS) bt Paula Badosa (ESP) 6-4, 6-2
Beatriz Haddad Maia (BRA) bt Bernarda Pera (USA) 6-3, 5-7, 6-4
Angelique Kerber (GER x2) bt Polona Hercog (SLO) 6-2, 6-2