Swansea manager Steve Cooper criticised referee Keith Stroud for failing to send off Reading's Lucas Boye in their 1-1 draw at the Liberty Stadium.
The Swans' flying start to the season had hit a speed bump after a draw and a defeat in their previous matches, but they raced into the lead after three minutes.
Baston spotted his opportunity, moved into the space and glanced in a header for his sixth league goal of the season to return to the top of the Championship goalscoring charts.
Boye was lucky to stay on the pitch on the stroke of half-time after man-handling Matt Grimes following an early booking for a late challenge on Roberts.
But Stroud kept his cards in his pocket and Boye was removed from the action at half-time by Jose Gomes.
Reading piled on the pressure after half-time but left it until the 90th minute to finally unleash a shot on goal.
A wayward cross from the left sat up perfectly for wing-back Yiadom on the edge of the area and he lashed a lethal shot across the face of goal and into the top corner to snatch a share of the points.
"They should definitely have been down to 10 men," said Cooper. "We are definitely on the end of some poor decisions at the moment.
"I was pleased we had an experienced referee today for the first time, as we seem to be getting the ones who are maybe a bit new to it. But we still got the same luck.
"He is going to have his excuses and his reasons, but I could tell he and the fourth official knew they probably were not at their best.
"Maybe it has an impact, for them they know they got away with one. I don't want to dwell on it too much. It was a clear second yellow card and the referee has made awful decision."
The draw ended Reading's three game losing streak in the league and Gomes defended the referee's decision not to send Boye off.
"I think the referee followed the same criteria because a few minutes before a Swansea player caught my player by his shirt and shorts and he didn't show a yellow card. So he followed the same criteria.
"Lucas Boye is a fighter, he is really physical and he uses his body. He adapted really well to the Championship and I thought it was better not to expose him to the chance he might get a yellow card so I took him off.
"I'm happy because from the bench I watched my team playing very positive football. Both teams were playing open football and were trying to win.
"For the way we controlled the ball in the offensive half we should have scored more goals. It would have been so unfair if we went back to Reading with no points.
"It's a very important point, if we couldn't win at least we got a point and in the way we played."