The Hammers set up the win with goals in the first-half from Crysencio Summerville and Taty Castellanos.
Parker said afterwards: “It was a tough day. A really disappointing outcome to a really important game. You can see a fragility to us at the moment. It was an edgy environment. You could feel it in the stadium.
“Their two goals took the sting out of us. We gave ourselves a mountain to climb.”
He also said, “We showed a real endeavour in the second half but we didn’t take our chances. I can’t fault the effort of the boys. I can’t be hugely critical today. But ultimately we fell short.”
On the home support, Parker stated: "I can understand some of the frustrations. Of course I can.
“There’s other aspects that I don’t understand. Players being told they’re not fit to wear the shirt or I’m getting sacked in the morning after the first goal went in. I just don’t think that’s helpful. But all we can do to change things is to win football matches.
“Today is probably a reflection of the difficult moment we find ourselves in at in this time.”