Roger Federer saw his unbeaten start to 2018 come to an end by Juan Martin del Potro at the BNP Paribas Open in Indian Wells, California on Sunday.
Argentine del Potro fought back to defeat the evergreen top-ranked Swiss in three sets, winning 6-4, 6-7, 7-6.
After coming out on top in the first set, del Potro held a match point at 8-7 in a second set tie-break, only for his errors to allow Federer a route back into the contest by forcing a third, and deciding set.
In the third set, Federer had the opportunity to serve for the match, holding two match points of his own, however del Potro was able to hold off any title-winning celebrations that the 36-year-old Swiss had foreseen to force deuce - before eventually securing the break.
In the final set tie-break, del Potro, who has recently returned to the sport following a series of wrist injuries, raced into a 6-1 lead, closing out the victory on his third match point after Federer's forehand failed.
The win for del Potro meant that he clinched his first Masters title on the men's tour at the age of 29.
Despite seeing his unbeaten streak come to an abrupt end in the thrilling three-set affair, Federer praised del Potro's performance after digesting the result.
“What a battle today,” Federer wrote on Twitter, before going onto praise his Argentine opponent.
“Congrats on a fantastic tournament and match, @delpotrojuan.”
Having got his hands on the trophy, del Potro echoed Federer's words, going onto speak highly of the tennis great, who had previously won 17 straight matches.
“I’m still shaking, I think this is the worst part for me,” del Potro said in his victory speech.
“First of all I want to congratulate Roger to a great week and great success in this historical year.
“You’re making history and I’m so happy to be just behind you, seeing what you do.
“It’s amazing for our sport and for the life so thank you very much.”