Grand Slams are the pinnacle of the sport, where every professional player aspires to do their best. In men's tennis, Grand Slams follow a best-of-five set format and offer a stern examination of a player's credentials.Despite the unique challenges associated with playing Grand Slams, there are several players who have endured very few defeats in the opening round of Majors.On that note, let's have a look at 10 players in the Open Era who have had the best win% in the first round at Grand Slams.(Note: Only players who have played at least 20 tournaments have been considered for this list)#10 Andy Murray - 90.19% (5 losses in 51 appearances)Andy MurrayThree-time Grand Slam champion Andy Murray has endured only five first-round exits in 48 Major appearances.Murray, a former World No. 1, had three first-round exits in his first 10 Grand Slam appearances -- Australian Open 2006, Australian Open 2008 and Roland Garros 2006.It took more than a decade for Murray to once again fall at the opening hurdle (2019 Australian Open). A year later, the Brit, on the comeback trail following hip surgery, fell in the first round of the 2020 US Open.Heart. Determination. Murray.@andy_murray seals a battling victory on his return to singles action at #Wimbledon, overcoming Basilashvili 6-4, 6-3, 5-7, 6-3 pic.twitter.com/Z2OjYYyrjy— Wimbledon (@Wimbledon) June 28, 2021#9 Milos Raonic - 91.17% (3 losses in 34 appearances)Milos RaonicCanada's Milos Raonic, who is not playing at Wimbledon this year because of injury, has endured only three first-round exits in 34 Grand Slam appearances.Raonic's best moment under the sun came when he became the first player to beat eight-time champion Roger Federer in a Wimbledon semifinal in 2016. The Canadian lost the final in straight sets to Andy Murray though.He's done it again...The magnificent Andy Murray is #Wimbledon champion for a 2nd time after beating Milos Raonic pic.twitter.com/XS17gcR3fA— Wimbledon (@Wimbledon) July 10, 2016Raonic fell in the first round on his Grand Slam debut at the 2010 US Open. He also failed to clear the opening hurdle at 2011 Roland Garros and the 2018 Australian Open.#8 Juan Martin Del Potro - 91.89% (3 losses in 37 appearances)Juan Martin Del Potro (right) won his only Grand Slam title at the 2009 US Open.Former US Open champion Juan Martin Del Potro, who hasn't been on the tour for more than a year, has a good record in Grand Slam first-round matches.Despite being hindered by injuries, the Tandil native has fallen in the first round at a Major only thrice in 37 appearances.After falling in his opener thrice (2006-07 Roland Garros, 2006 US Open) in his first four Major appearances, Del Potro has not been beaten in the first round at a Grand Slam.The highlight of Del Potro's career was his victory over Roger Federer in the final of the 2009 US Open to win his first Grand Slam title.2009. Men's singles final. Five thrilling sets. 🤩11 years ago, a 20-year-old Juan Martín del Potro left Flushing Meadows with his first major title after defeating Roger Federer.Full Match ➡️ https://t.co/gAkP7A77gd pic.twitter.com/OSColFgJcI— US Open Tennis (@usopen) May 24, 2020The Argentine also made the US Open final in 2018 but fell short against Novak Djokovic. Since a fourth-round exit at Roland Garros in 2019, Del Potro is yet to appear in a Grand Slam.#7 Stefan Edberg - 92% (4 losses in 50 appearances)Stefan EdbergSix-time Grand Slam winner Stefan Edberg fell only four times in the first round of a Major during his illustrious career. Edberg endured two first-round exits apiece at Flushing Meadows (1983 and 1990) and Roland Garros (1990 and 1994).The Swede enjoyed a riveting rivalry with Boris Becker at Wimbledon, playing three consecutive finals between 1987 and 1989, winning twice and losing once.Stefan Edberg v @TheBorisBecker.30 years on, take a trip down memory lane to the #Wimbledon trilogy that had everything...Live now on YouTube 👇— Wimbledon (@Wimbledon) June 22, 2020Edberg came close to winning the Career Grand Slam, but fell to Michael Chang in the 1989 Roland Garros decider.#6 Arthur Ashe - 92% (2 losses in 25 appearances)Arthur AsheTwo-time Grand Slam champion Arthur Ashe had an almost impeccable record in Grand Slam first-round matches.The 1970 Australian Open and 1975 Wimbledon winner fell at the opening hurdle only twice in 25 Grand Slam appearances. Both of those defeats were at Wimbledon (1978-79), with the latter marking Ashe's last appearance at a Grand Slam tournament.1975 Wimbledon Men's Singles Final: Arthur Ashe vs Jimmy Connors: http://t.co/ziROmbGm0K via @YouTube— Wimbledon (@Wimbledon) May 31, 2013Ashe famously beat defending champion Jimmy Connors to win the 1975 Wimbledon title.#5 Yevgeny Kafelnikov - 92.1% (3 losses in 38 appearances)Yevgeny KafelnikovYevgeny Kafelnikov is one of the few Russian players to have won multiple Grand Slams. Kafelnikov triumphed at Roland Garros in 1996 and Australian Open in 1999 during a short but storied career.That year(1996) i played 171 total matches🤦🏼‍♂️! 4singles titles(Adelaide,Prague,RG,Lion) and 4 finals(Rotterdam,Halle,Bercy,Moscow) and 5 doubles titles-4 with Daniel Vacek=OMFG🤷🏻‍♂️👍🏻👍🏻 https://t.co/g7Xvvx1nTY— Kafelnikov Yevgeny (@KYevgeni) September 22, 2019The former World No. 1 suffered all three of his Grand Slam first-round losses at Wimbledon, in 1996, 1998 and 2003.Kafelnikov made his last Grand Slam appearance at the US Open in 2003, where he fell in the third round.#4 Roger Federer - 92.5% (6 losses in 81 appearances)Roger FedererRoger Federer, one of the best players to have graced the sport, has carved out a plethora of records during a long and distinguished playing career."My English is not good enough!"Even at 39, you never stop learning - right, @rogerfederer?#Wimbledon pic.twitter.com/5BALP53NDA— Wimbledon (@Wimbledon) June 29, 2021All six of Federer's first-round defeats at Grand Slams came before he made his Major breakthrough at 2003 Wimbledon. The Swiss fell at the opening hurdle at Roland Garros (1999, 2000, 2002) and Wimbledon (1999, 2000, 2002).Since then, Federer's earliest exit at a Major came in 2013 when he fell to unheralded Ukrainian Sergiy Stakhovsky in the second round.The 20-time Grand Slam champion narrowly averted a first-round exit at Wimbledon this year. With the scores level at two sets apiece, his first-round opponent Adrian Mannarino was forced to retire due to injury.#3 Rafael Nadal - 96.77% (2 losses in 62 appearances)Rafael Nadal at 2020 Roland GarrosRafael Nadal has a stellar record in the opening round at Grand Slams, falling just twice in 62 appearances.The Spaniard faltered in the opening round of a Major for the first time at Wimbledon in 2013, 10 years after his Grand Slam debut. Nadal's only other setback in this round of a Major came against his compatriot Fernando Verdasco at the 2016 Australian Open.The Spaniard currently shares the record for most Grand Slam titles with Roger Federer (20).For the 13th time...@RafaelNadal is King in Paris.#RolandGarros pic.twitter.com/ICbgLmYj0T— Roland-Garros (@rolandgarros) October 11, 2020#2 Novak Djokovic - 96.92% (2 losses in 65 appearances)Novak DjokovicNovak Djokovic scripted history at Roland Garros this year when he beat Stefanos Tsitsipas in the final to become the first player in the Open Era to win each Grand Slam tournament at least twice.Earlier in the tournament, the Serb downed 13-time champion Rafael Nadal in a grueling four-set semi-final.🇷🇸 Djokovic Jubilation 🇷🇸@DjokerNole lands Grand Slam title No.19 and his second in Paris, defeating Tsitsipas 6-7(6), 2-6, 6-3, 6-2, 6-4.#RolandGarros pic.twitter.com/lsG64N0s9q— Roland-Garros (@rolandgarros) June 13, 2021The Serb has fallen only twice in the opening round at a Grand Slam. Incidentally, both those defeats happened at the Australian Open (2005-06), where he is a record nine-time champion.#1 Bjorn Borg - 100% (0 defeats in 26 appearances)Bjorn BorgEleven-time Grand Slam champion Bjorn Borg is the only player never to have fallen in the opening round (minimum of 20 Major appearances).The six-time Roland Garros and five-time Wimbledon winner made only 26 Grand Slam appearances but never failed to clear the first-round hurdle.Legend looking on. No pressure 😃Pleasure to see our six-time champion, Bjorn Borg.#RolandGarros pic.twitter.com/hF7nEW1uwA— Roland-Garros (@rolandgarros) June 13, 2021Borg remains the only player in the Open Era to complete the Roland Garros-Wimbledon double thrice (1978-1980). He came close to doing it for a fourth time the following year, only to fall to John McEnroe in the Wimbledon final.🇸🇪 Bjorn Borg has never lost a R128 in Slams. Djokovic and Nadal only 2#Wimbledon pic.twitter.com/bCytrGtNrf— TennisMyLife (@TennisMyLife68) June 30, 2021