WATCH: Del Potro shows positive signs in comeback

Juan Martin del Potro made his much anticipated return to the tour in Madrid this week, playing his first tournament since Delray Beach, and just his second since suffering a fractured kneecap in Shanghai last year.

The world No. 8 and defending US Open finalist first eased back into things by playing doubles alongside Kei Nishikori; they won their opening match in a super tiebreak versus Fabio Fognini and Robert Lindstedt.

Del Potro's singles debut, on Wednesday, was a battle as well. He lost a match point on Laslo Djere's serve, and ultimately lost the match: 6-3, 2-6, 7-5 in two hours and 22 minutes.

"Coming to this tournament is one more step for me in my rehabilitation and my final recovery to feeling completely fit again and completely healing the knee injury," Del Potro said before the tournament.

He's since been eliminated in doubles as well, by Jamie Murray and Bruno Soares. But Del Potro, who's truly been through it all in his career, also showed, by his friendliness and determination throughout, why he remains one of the most beloved players on tour.