The Exiles suffered their fourth consecutive loss of the season on Friday night as they were beaten 10-46 at the Kassam Stadium.
However, Burnell believes that his players were unfairly penalised throughout the match by official Luke Pearce.
"At 12-10 at half time we were more than in the game but crucially decisions went against us," he is quoted as saying by BBC Sport.
"The penalty count was 20-7 against us and I can't explain why. It seems that we are doing certain things and are penalised and the opposition are doing the same but they are not.
"It's easy to look at the scoreboard and we will have to learn to play for 80 minutes not 60, but it seemed the game changed on its head almost on a flip of a coin."
London Welsh return to Aviva Premiership action next Saturday when they travel to Harlequins.