"Whoever won that first set had big momentum".
"Whoever won that first set had big momentum, it was like an hour and 30 minutes, and in these conditions, when it's very slow and heavy, to be coming back is hard".
A remarkable effort saw Del Potro break back for 5-5, before he dropped serve and allowed his opponent to control proceedings and take the set 7-5 with his fourth ace of the day.
Murray, the 2016 runner-up, reached the third round with a bruising 6-7 (3/7), 6-2, 6-2, 7-6 (7/3) win over Martin Klizan of Slovakia.
"Andy proved he is a real No. 1", said Del Potro.
"I played a good match and am disappointed to lose", said Edmund.
Rafael Nadal laid down a marker as he chases his 10th French Open title with his most one-sided ever victory at Roland Garros.
Del Potro, whose career has been blighted by a recurring wrist injury, needed a good start against the world No.1 but when he lost a tight first set tiebreak, the stage was set.
Such an outcome left Juan Martin with nothing in the tank, and he lost his serve 3 times in the third set, unable to fight like he did in the previous two sets, and it didn't take long for Andy to cross the finish line in just under 3 hours, avoiding to spend extra time on the court and entering the second week. â.
After searching for consistency in his opening two matches, Murray found something approaching his best form to win the most anticipated match of the first week. "I did a good clay season and I'm looking forward to playing [well on] the grass". If he has a great tournament here, he can feel great going onto grass and have a great Wimbledon and in six weeks' time.More news: UK leader holds alliance talks with NIreland party chief
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Murray vs. del Potro provided the most enticing matchup, a pair of past major champs providing high-quality play and intense competition.
"Both of us had some chances in the first set and the second set was the same".
Del Potro is still working his way back to his rightful ranking after the wrist problems that nearly ended his career, and the big question was how he would pull up physically.
Wawrinka will face Italy's Fabio Fognini for a place in the fourth round.
"It was tough. I think he was playing much better than me in the first set".
"The tactical side is very important for me".
It was hard to know whether it was cause or effect, but Murray was broadly more calm than he has been for months, and spared his support box some of his more splenetic behaviour.
Marin Cilic is yet to drop a set in this year's tournament.
Anderson, who conquered Australia's Nick Kyrgios in the second round advanced to the fourth round with a five-set win over Briton Kyle Edmund. Fernando Verdasco easily got past No. 22 Pablo Cuevas 6-2, 6-1, 6-3.
The unseeded Cornet beat ninth-seeded Agnieszka Radwanska of Poland 6-2, 6-1, and the 28th-seeded Garcia beat Hsieh Su-wei of Taiwan 6-4, 4-6, 9-7 in remaining third-round play.