Sampras’ weapon of choice helped him win 14 Grand Slam titles and top the ATP rankings for 286 weeks. Both of those marks were men’s records at the time, and they seemed destined to stand for years—until Sampras’ No. 1 Swiss fan, Federer, broke them both less than a decade later.
http://www.tennis.com/pro-game/2015/04/mens-final-1-roger-federer-vs-3-pete-sampras/54662/
Rod Laver won the U.S. Open in 1969 to complete his second Grand Slam. He also won all four major tournaments in 1962. Credit Associated Press. In the days leading up to the 1969 United States Open, pressure was mounting on Rod Laver.
https://www.nytimes.com/2015/08/31/sports/tennis/the-stress-of-the-tennis-grand-slam.html
In the Grand Slam events in 1984, Navratilova lost only one match, to Helena Sukova in the semifinals of the Australian Open, which was then the season-ending tournament in December. Navratilova once won six major tournaments in a row, in 1983-84, but she never won four in the same year.
https://www.nytimes.com/2015/08/31/sports/tennis/the-stress-of-the-tennis-grand-slam.html
There are really two ways to answer this one: The first is to address how Pete's game, as it existed in his prime, would have matched up with the players of the Big 4 Era if he was simply plunked down 10 years later. This would mean playing the Big 4 during their own era on the surfaces as they exist currently.
https://www.quora.com/How-many-Grandslams-would-Pete-Sampras-had-won-had-he-played-in-the-Big-4-era
1. Federer Phase (2002-2005) - This was a time around when Federer began his dominance. Federer won 6 grand slam titles. (3WIM + 2USO +1AO) Agassi was still there in this time. Now if Sampras would've begun his career in 2003, I would say he would've pushed Agassi at the AO to his limits. I think his first slam could've been French Open given that it witnessed a lot of one slam wonders during this time.
https://www.quora.com/How-many-Grandslams-would-Pete-Sampras-had-won-had-he-played-in-the-Big-4-era
As a young player, Federer idolized the champions of the 1980s and 1990s, attackers like Boris Becker, Stefan Edberg, and Sampras, who used their one-handed backhands to move forward whenever they could. Federer went so far as to swing the same Wilson Pro Staff that Sampras did, and why not?
http://www.tennis.com/pro-game/2015/04/mens-final-1-roger-federer-vs-3-pete-sampras/54662/
Catching up with Pete Sampras as Roger Federer tries to break his Wimbledon record. WIMBLEDON, England – It was 15 years ago that American Pete Sampras won his last of seven Wimbledon titles, breaking Roy Emerson's Open Era Grand Slam record with his 13th overall, hoisting the trophy on Centre Court as the clock ticked past 9 o'clock in the evening.
https://www.usatoday.com/story/sports/tennis/wimb/2015/06/30/pete-sampras-roger-federer-wimbledon-record/29505207/
Sampras and Federer played just once, at Wimbledon in 2001, when Sampras was nearly 30 and declining, and Federer was nearly 20 and ascending. That year Wimbledon changed to a hardier all-rye grass, one that produced a higher bounce and ushered in an era of baseline dominance on Centre Court.
http://www.tennis.com/pro-game/2015/04/mens-final-1-roger-federer-vs-3-pete-sampras/54662/
The Stress of the Slam. Rod Laver won the U.S. Open in 1969 to complete his second Grand Slam. He also won all four major tournaments in 1962. In the days leading up to the 1969 United States Open, pressure was mounting on Rod Laver.
https://www.nytimes.com/2015/08/31/sports/tennis/the-stress-of-the-tennis-grand-slam.html
Sampras would win one more major in his career, a fairytale finish at the U.S. Open in 2002 that gave him a 14th and final major crown. Sampras wouldn't play another match after that win over Andre Agassi, retiring from the game in 2003 and remaining a largely absent figure in the sport of tennis since.
https://www.usatoday.com/story/sports/tennis/wimb/2015/06/30/pete-sampras-roger-federer-wimbledon-record/29505207/
how many majors did pete sampras win so far
Pete Sampras won 14 majors so far.  Pete Sampras win 14 majors so far.