Career
Venkov was raised in Septemvri Sofia"s youth teams, then he signed with Litex. In 2004 he was loaned for six months to Belite orli Pleven and played in the B PFG. During the 2009/2010 and 2010/2011 seasons he lost his place in the first team for Litex and eventually was transferred to Lokomotiv Plovdiv in July 2011. On 15 March 2012, Venkov scored a last-minute goal against Levski Sofia in a 1/4 final match of the Bulgarian Cup to level the score at 1–1 and send the game into extra time.
CSKA Sofia
During the summer of 2012 (following a change of ownership in Lokomotiv Plovdiv), Venkov signed a contract with CSKA Sofia, but was initially unable to play in official matches for the team due to a transfer prohibition imposed on the "redmen".
The ban was lifted in mid September 2012 and Venkov made his official debut on 22 September, in the 0–1 away loss against Ludogorets Razgrad. Cherno More
On 8 July 2013, Venkov signed a two-year deal with Cherno More Varna.
He made his league debut in a 1–0 away loss against Chernomorets Burgas on 19 July, playing the full 90 minutes. On 7 April 2015, Venkov scored his first goal for Cherno More in the 48th minute of a Bulgarian Cup match against Lokomotiv Plovdiv.
Having been appointed vice-captain for the 2014-2015 season, Venkov was promoted to club captain after the departure of former captain Kiril Kotev in May 2015.
On 23 May, Venkov signed a one-year contract extension, keeping him at Cherno More until 30 June 2016. A week later, he received his first major honours with Cherno More, captaining the team as they beat Levski Sofia 2–1 in the 2015 Bulgarian Cup Final.