"I don't know why I could never get to any level that I was happy with today".
Ranked 13th in the world after lengthy spells off the court with an elbow injury, Djokovic is training with Vajda for the first time since last year's Monte Carlo Masters.
Nowhere more so than Monte Carlo where a year ago he became the first player to win the same ATP tournament 10 times. Then I felt great practicing in Acapulco, playing very well, but then just the day before. He's more like a brother, a father.
"I feel that I'm playing well".
Here's a look at the main talking points ahead of the action on the red dirt of the Principality.
Djokovic moved far more freely and was calm and composed throughout, teaching his countryman a lesson to set up a second-round encounter with Borna Coric.
Djokovic started strongly, dropping only three points on serve as he cruised to a first-set bagel which was sealed with a fierce return victor.
A two-time champion in Monte Carlo, Djokovic put Lajovic under pressure from the start, a tame forehand into the net putting Djokovic 2-0 up and he had a double break courtesy of an errant backhand from the outsider.
But the qualifier was unable to make the most of those openings, and Djokovic broke in game four as Lajovic fired wide.
"Australia was a tough moment, of course, being in that quarter-final, winning the match and having that problem, having a good chance". He has only ever played three matches at the tournament and incidentally, his last clash there was a three-set defeat to Berdych, who takes on the Japanese in the opening round next week. He has not won a Grand Slam tournament since the 2016 French Open.
The draw has not been kind to the comeback man as he finds himself in the half of the draw, which also has the likes of former world number one Novak Djokovic and last season's clay-court star Dominic Thiem.
Nishikori, down to 36 in the rankings, received on-court treatment for a sore wrist but battled his way into round two in his first appearance in the tournament for six years. I always enjoy this Europe season.
The 28-year-old is unseeded as his ranking has slipped to 39 in the world due to injury.
Last year's runner-up Albert Ramos-Vinolas beat American Jared Donaldson 6-3 6-3 in a match marred by a heated argument between the 21-year-old Donaldson and the chair umpire over what he thought was an erroneous call.