NIGEL Clough thought his team were well in the game at Hull until Jackson Irvine's red card in the 38th minute.
The Brewers boss said: "There were several turning points in the game today and the red card was the most important one.
"Their first goal was offside and then Lucas (Akins) was onside and his goal was ruled out. We then thought Jackson's second yellow card was harsh so if you factor in all those three and losing Stephen Warnock it was very difficult for us."
In terms of the red card, the Albion manager said the "petulance of the first yellow card was upsetting" but was disappointed with the second yellow card decision which will mean the Australian will be ruled out at Middlesbrough.
After the red card the Brewers struggled to contain the home side.
Clough said: "Then with the quality of their players and their finishing, without Stephen Bywater it could have been six. He made some outstanding saves and Jake Buxton played well - Lucas Akins battled away up front.
"But we certainly played well enough in the first half an hour today with 11 men and created chance after chance. We have to start making the most of them, similar to the start of last season."
The Brewers will also now be without Warnock on Tuesday.
Clough said: "We will know early next week but he certainly won't be available at Middlesbrough."