- Djokovic makes semis when Tsonga retires
- Third retirement or walkover to world No. 1
- Defending champ next faces France's Monfils
(CNN)You've heard of the expression "Better to be lucky than good?" But what if you are both lucky and good?
At this year's US Open, Novak Djokovic -- one of tennis' all-time greats with 12 majors -- is a prime example.
When Jo-Wilfried Tsonga retired trailing the world No. 1 in Tuesday's quarterfinals 6-3 6-2, it marked the third time during the tournament that Djokovic had benefited from a walkover or retirement.
It all began in the second round when Czech Jiri Vesely withdrew with a forearm complaint. Then in the third round, Russia's Mikhail Youzhny called it quits with a hamstring injury while behind 4-2.
Tsonga stopped on Arthur Ashe stadium due to a left knee problem to extend Djokovic's good fortune.
"I can only wish all of my opponents a speedy recovery," Djokovic, who next faces another Frenchman, Gael Monfils, told reporters.
Saving energy is just what the doctor ordered for the defending champion, since the Serb entered the event with a left wrist injury and has been treated for a right arm issue more than once since the year's final grand slam began.
"In this stage of the season, considering some physical issues I have had in the last month, month and a half, this was the scenario that I needed and I wished for," Djokovic said. "I got a lot of days off and recovered my body.
"Right now I'm feeling very close to the peak. That's the position where I want to be."
Indeed Djokovic -- bidding to claim three majors in a year for the second straight season -- wasn't concerned about rust being a factor if he had to play a fourth or fifth set in the semis or potentially, the final.
"I have played so many times," he said. "I was so many times in this particular situation where I had long matches on the road to the semis of a grand slam. Also had some grand slams where I didn't spend too much time on the court.
"It really just depends how you feel, how your season has been, how many matches you have played throughout the year.
"As I said, this scenario ... was ideal at this stage."
The form book suggests Djokovic will face second-ranked Andy Murray -- tennis' most in-form player -- in Sunday's final.
Murray meets Kei Nishikori in Wednesday's quarterfinals, with the Scot crushing Japan's sixth seed only last month on the way to winning gold at the Olympics.
The other men's quarterfinal pits 2009 winner Juan Martin del Potro against twice grand slam champion Stan Wawrinka. The Argentine -- ravaged by wrist injuries -- upset Wawrinka at Wimbledon before continuing his career revival by taking the silver medal at Rio 2016.