A quote that is thrown about a lot in football discourse is "Attack wins you games, defense wins you titles." Often, the individuals holding the defense on their shoulders are the goalkeepers. An effective barricade is only as good as its base.Jurgen Klopp learned that the hard way. His fortification of Anfield started with the acquisition of Virgil van Djik, but remained incomplete until the subsequent arrival of Alisson Becker. In this era of flashy forwards and ball-playing centre-backs, the hard work put in by goalkeepers often goes unnoticed.Every club prefers to employ two decent keepers in their ranks. After all, a no-nonsense defender won't be able to keep the ball out of his net all on his own. Second-choice goalkeepers often spend most of their careers with nominal game-time and recognition.Exceptional backup goalkeepers who defied the oddsDespite these limitations, there have been a few goalies who rose through the ranks and established themselves as their club's number one. Nick Pope was comfortably behind Tom Heaton as long as the latter remained fit. However, when given a rare chance due to Heaton's injury, Pope proved to be even better than his superior. Pope's incredible goalkeeping meant Heaton was soon shipped to Aston Villa and he is now effectively third-choice at Manchester United.Our EmiAugust: 2020- Wins the FA Cup- Wins the Community ShieldSeptember: 2020- Joins Aston VillaMay: 2021- Finishes PL season with 15 clean sheetsJune: 2021- Argentina debut- Seals #1 spotJuly: 2021- Wins Argentina's first Copa since 1993@emimartinezz1 🔥🔥🔥 pic.twitter.com/cEyaveRA8F— kieran N (@roguevilla) July 14, 2021But no goalkeeper has had a more meteoric rise than Emiliano Martinez in recent times. The Copa America 2021 winner was playing in the second tier of English football just two years back. A scarce opportunity at the end of the 2019-20 season turned his career upside down and he was picked by Aston Villa to be their number one in the following season.Here we take a look at five such unsung heroes who have played second fiddle to other goalkeepers, despite having substantial capabilities -#5 Mathew Ryan | Real SociedadMathew Ryan (in pic) and Robert Sanchez shared minutes at the post last season for BrightonMathew Ryan has been the undisputed first-choice goalkeeper at the Amex Stadium ever since his transfer from Valencia was confirmed. However, he recently ended his four-year stay at Brighton with a permanent switch to Real Sociedad.The Australian veteran was inexplicably dropped from the squad in December 2020, after a 3-0 loss to Leicester in the Premier League. According to reports, Graham Potter informed the Aussie goalkeeper that he needed to find a new club after that fateful game. Robert Sanchez has since replaced him between the sticks and gone from strength to strength.In an interview with Optus Sport, Ryan relayed his thoughts about being axed from the Seagulls, stating:"I am not the first player to be in the situation where you are not wanted or not perceived as being the best man for the job. There are a number of reasons that can happen, whether it is a performance thing, an opinion of a manager, or you never really know if there is a political or business thing behind decisions.”Ryan was subsequently loaned out to Arsenal for the remainder of last season, where he worked as Bernd Leno's backup. The 29-year-old shot-stopper played a grand total of three games for the Gunners before returning to Brighton. Ryan was then perpetually released by the Seagulls at the end of the 20/21 campaign. He recently joined Real Sociedad on a free transfer.MAT RYAN > Real SociedadBrighton legend, Mat Ryan went on loan to Arsenal last season, but it didn't work out. The Aussie has gone back to Spain now tho, on loan at Real Sociedad.#Brighton #MatRyan #RealSociedad pic.twitter.com/0Kdkmiw0fe— Man-On! (@ManOnFutbol) July 16, 2021Sociedad first-choice keeper Álex Remiro kept 18 clean sheets across all competitions for the Whites and Blues last season. Resultantly, Ryan will most certainly act as the backup goalkeeper at the Anoeta Stadium, come next season.#4 David Ospina | NapoliDavid Ospina's heroics took Colombia to the semi finals of Copa America 2021David Ospina often seems older to many than his actual age, but he is only 32. The Colombian goalkeeper was signed by Napoli from Arsenal, initially on a season-long loan. The club made the move permanent in 2018 to cover for the injured Alex Meret.An acrobatic keeper with commendable ball control, Ospina has been a silent warrior throughout his career. He was regarded as a promising prospect in his earlier days at Nice, where he went on to make 189 appearances.Ospina was snapped up by Arsenal in 2014 for an undisclosed fee. He was soon handed the number one role after regular goalkeeper Wojciech Szczęsny was fired due to professional reasons. The former Atletico Nacional shot-stopper was eventually replaced by Petr Cech the following year, despite enjoying an impressive debut campaign at the Emirates.Ospina has played a rotational role in Naples ever since his arrival in 2018 on loan. He did become the preferred goalkeeper for a brief period of time under Gennaro Gattuso. But he was soon demoted to the bench following some high-profile errors.Ospina not only saved two penalties in the shoot out to guarantee Colombia's place in the semi-finals of Copa America, but he did it while completing his 112th cap for the Cafeteros, becoming the most capped Colombian player ever, surpassing El Pibe Valderrama (111 caps) pic.twitter.com/MVzJSyGiUH— AJ (@juveaj) July 4, 2021Nevertheless, the Medellin-born goalie has been an ever-present member of his national side. Ospina was instrumental in Colombia's run to the Copa America 2021 semi-finals, keeping three clean sheets in six matches. He also heroically saved two penalties during a shootout victory in the quarter-final fixture against Uruguay.