The Tykes signed Haynes from Bristol City for an undisclosed earlier this week in time for him to make his debut in the 1-1 home draw with Swansea. The 23-year-old has signed a two-and-a-half-year deal.
Haynes said: "It's been a while since I've played 90 minutes and I felt I worked hard.
"Hopefully I can get my fitness up and show the real me."
Haynes thought he had marked his first appearance with a goal after slamming in a rebound after Kieran Trippier's 33rd-minute shot had come back off Swansea goalkeeper Dorus De Vries, but the strike was ruled out for offiside.
Haynes added: "It was down to a coin toss really. The linesman thought I was offside - I didn't, but these things happen in football. I just want to play well and score goals here."
Source: PA
