A goalkeeper, Tzanev moved from his native New Zealand to England in 2006 and trained with a Chelsea development programme before joining the academy at Crystal Palace. He moved to join the academy at Brentford and progressed through the ranks to sign a Youth Development contract in 2013, which enabled him to continue his education through to his A-levels. He made 39 appearances for the youth team during the final three seasons of his youth career and won the club's Youth TeamPlayer of the Year award for his performances during the 2014–15 season. Tzanev was awarded a one-year Development Squad contract at the end of the 2014–15 season, but made just eight appearances before his release at the end of the 2015–16 season.
During the course of the 2016–17 season, Tzanev trialled with EFL clubs Wycombe Wanderers and Hartlepool United. He joined the AFC Wimbledon Development Squad on trial in March 2017 and impressed enough to be awarded a contract until the end of the season on 28 April 2017. He was called into the first team squad for the club's final match of the season versus Oldham Athletic and remained an unused substitute during the 0–0 draw. Tzanev signed a new contract on 8 May 2017 and was an unused substitute on five occasions during the 2017–18 season. Tzanev signed a new contract in July 2018, but received just one call into the first team squad during the first half of the 2018–19 season, before departing Kingsmeadowon loan until the end of the campaign in January 2019. He signed a contract extension in February 2019 and injury to first-choice goalkeeper Nathan Trott allowed him to make his debut for the club on the opening day of the 2019–20 season, in a 2–1 defeat to Rotherham United. Tzanev made three further appearances before spending the remainder of the season away on loan.
On 18 January 2019, Tzanev joined Isthmian League Premier Division club Potters Bar Town on a one-month loan, which was subsequently extended until the end of the season. He made 15 appearances during his spell.
On 15 November 2019, Tzanev joined National League club Sutton United on a loan which was later extended until the end of the 2019–20 season. He made 19 appearances before the season was ended early.
International career
Tzanev won his maiden call up to the New Zealand U20 squad for two friendlies versus Uzbekistan in April 2015 and made his debut in the second match, playing the full 90 minutes. He was called into the New Zealand squad for the 2015 U20 World Cup, held on home turf and he made two appearances as the All Whites reached the last-16. He was subsequently called into the U23 squad for the 2015 Pacific Games, but failed to make an appearance. Tzanev received his maiden senior international call-up for a friendly match versus Canada on 25 March 2018 and was an unused substitute during the 1–0 defeat. He was named in a youthful squad for the 2018 Intercontinental Cup and made his full international debut with a start in a 1–0 victory over Chinese Taipei on 5 June 2018.
