Ernests Gulbis pulled off the biggest shocker of the day Sunday afternoon at Roland Garros. The 25-year-old Latvian, seeded No. 18, knocked off Roger Federer 6-7 (5), 7-6 (3), 6-2, 4-6, 6-3 in a 3-hour, 42-minute fourth-round thriller. It was the first time since 2004 that the No. 4-seeded Federer has failed to reach the quarterfinals at the French Open. For Gulbis, it was his second Grand Slam quarterfinal appearance, his first coming six years ago, also in Paris. “It’s the biggest win of my career,” Gulbis said. “Sorry I had to win. I know how everyone likes Roger. It was a tough match but this is sport. I’ve been playing very well in France. I won tournaments in Marseille and Nice, hopefully Paris is the next one.” Gulbis has always had a ton of talent and tremendous upside, but has underachieved so far in his career. This year, though, the 6-3 Latvian has recommitted himself to the hard work it takes to get to the top. The effort has paid off, resulting in a career-high No. 17 ranking. Except for back-to-back service breaks in the sixth and seventh games of the first set, service prevailed to force a tiebreaker in the opener. Gulbis led 5-3 in the tie-break, but Federer rallied for four straight points to take the set. There were a pair of back-to-back service breaks in the second set (games 1 and 2, and 8 and 9). The ninth game was particularly disastrous for Federer who was serving 5-3, 40-15 to go up two sets to love. Didn’t happen, as he was broken and then lost the tiebreaker. Gulbis buzzed through the third set, breaking twice and appeared to be on his way to a four-set win. Federer would have none of it, breaking in the fifth and seventh games of the fourth set, as Gulbis totally lost focus. The Latvian got a token break back in the eighth game after a medical timeout, but by then the set was done. Gulbis held his nerve when it mattered most in the fifth set, got the only break in the second game, and served it out for the huge win. “I’m clearly very disappointed not to come through with the win,” Federer said. “After the chance in the second set, fighting back in the fourth, not to play a better fifth set. There are a lot of regrets here now. But I think Gulbis did a good job of hanging around and clearly coming back in that second set was crucial for him, I think.” Gulbis hit 13 aces to seven for Federer, and won the battle of winners 53 to 42. Federer committed 58 unforced errors, while the go-for-broke Gulbis had 53. Gulbis will play Czech Tomas Berdych in the quarterfinals.