Wesley says he enjoyed netting his second goal in Aston Villa colours, but couldn't hide his frustration as it proved not to be the winning strike at Arsenal on Sunday.
The Brazilian poked us ahead for the second time of the afternoon on the hour mark at the Emirates, following a superb run and assist by Jack Grealish.
But his goal, which sent the 3,000-strong away end into raptures, proved in vain as the Gunners hit twice late on.
Wesley said: "We cannot lose like this. Arsenal had 10 men and we sat back and conceded two simple goals.
"We scored the second goal to get ourselves back in front, and then sat deep. We can't do that against big teams. They always come to score so it's difficult to win the game if you sit back.
"We have to continue and look to the next game, despite losing on Sunday. We have to work hard this week to change and make sure we start picking up points.
"I think the results are coming. We showed good signs today for 60 minutes, but then conceded the two goals.
"The manager was angry and agreed we can't lose like this – especially with 10 men.
"I'm very happy to score but I'd be happier if we won the game. I have to continue to work hard."