Chelsea attempted 34 shots in the game, their highest total in a WSL match since the start of last season.
James hit the ground running with a superb strike that flew into the roof of the net within 11 minutes and Chelsea fans expected the floodgates to open.
Villa barely laid a glove on their opponents and had only five touches in Chelsea’s box.
But, against the run of play, Noelle Maritz’s shot ricocheted off goalkeeper Hannah Hampton and bounced in off Chelsea defender Veerle Buurman late on.
Villa boss Natalia Arroyo threw her arms in the air and their supporters punctured the silence of disbelief that fell across Stamford Bridge.
“If you analyse the performance and the statistics, then you would say it’s crazy that we didn’t win. We created so many opportunities,” said Bompastor.
“The reality of football is that if we were two or three nil up then the game is over. It’s a completely different game in the second half.
“We have to speed up the game, keep that momentum and sustain that. We need to make sure we accelerate to kill the game. That is not what happened today.
“At the end, we are all frustrated because it’s not a good result.”
Bompastor’s biggest frustration was that she could do little to help.
With summer signing Melvine Malard out with a minor injury picked up in training and Mayra Ramirez still continuing her recovery, attacking options were limited.
England forward Aggie Beever-Jones led the line, taking the baton from recently-departed Sam Kerr, but her confidence is clearly low.
She had opportunities but scuppered them and when she did eventually put the ball in the net, it was ruled out for offside.
“What can we do in this scenario? We have to stay confident, stick together and work hard,” said manager Bompastor.
“In football some of these things are mental. It’s the mentality – the mindset of being ruthless and clinical in the box.
“The best teams don’t need many opportunities. They just need one or two and maybe that’s enough to win the game. That is something we need to work on.”