Swedish international centre-back Jansson spent three years with Leeds between August 2016 and July 2019 before being sold to Brentford ahead of the Championship season in which Marcelo Bielsa's Whites went up as champions.
Brentford then followed Leeds into the Premier League the following season by winning the 2020-21 Championship play-offs with Jansson as captain and the Swede led out the Bees in Sunday's Premier League clash at Elland Road.
Jansson's side trailed 1-0 at the break following a Tyler Roberts strike but looked set to leave West Yorkshire with all three points following goals from Shandon Baptiste and Sergi Canos within the first 16 minutes of the second half.
Leeds, though, salvaged a point as substitute Patrick Bamford kneed home a corner in the 95th minute upon his return from an ankle injury to seal a 2-2 draw and Jansson was left with contrasting feelings about the draw but was moved by his Elland Road return.
"Always special to play against your old teammates and it was emotional to see you all," said the 30-year-old Swede in an Instagram post.
"Good game and even though it's hard now, a good point.
"We gave it (our) all and fought until the last second and I'm very proud of our team. We go again Friday."
7. Leeds agree Joseph deal
Leeds United have finally agreed a deal to sign Espanyol striker Mateo Joseph, beating Liverpool and Man City to his signature. (Daily Mail) (Photo by George Wood/Getty Images) Photo: George Wood
8. Rangnick wants McGinn
Aston Villa star John McGinn has caught the eye of Manchester United's interim boss Ralf Rangnick. (The Sun) (Photo by Clive Rose/Getty Images) Photo: Clive Rose
9. Sutton makes Phillips claim
Chris Sutton believes Kalvin Phillips has had his "head turned" by transfer speculation after rumours of a bust up with Leeds United boss Marcelo Bielsa. (BBC Sport) (Photo by George Wood/Getty Images) Photo: George Wood