Coric earned a 7-6 (6), 3-6, 6-2 win over Federer Sunday, preventing the Swiss star from defending his title in Halle, Germany. His dropped points from last year's result allows Nadal to take over the top spot in the world rankings despite not competing in the tournament.
Nadal—who has won 12 straight matches with title wins at the French Open and Rome Masters—was just 150 points behind Federer entering the week in the latest standings and will move into first place Monday. He had been No. 1 in the world for three weeks before dropping to second last week.
The two star players have been in the top two spots of the rankings throughout 2018, with Federer in first for six weeks and Nadal in first for 16 weeks, including for June 25.
As for Federer, the latest loss was a disappointing one considering his past success at this event.
He had won the tournament nine times while reaching the finals 12 times in his career. He has also been nearly unstoppable on grass with 20 straight victories.
However, there is now a little bit of doubt for the 36-year-old heading into Wimbledon.