Tony Pulis accused Alexis Sanchez of "cheating'' to earn Arsenal an early free kick and insisted West Brom should have been awarded a penalty during their 2-0 defeat at the Emirates Stadium.
Jay Rodriguez was brought down in the area after a clumsy challenge by Shkodran Mustafi with the scoreline at 0-0, but he swiftly returned to his feet and forced Petr Cech to tip his shot onto a post as referee Robert Madley let play continue.
Sanchez by then had already won a free kick on the edge of the area after a challenge from Craig Dawson, but though he then curled wide, Pulis remained angry in his belief the Chilean had dived.
"The disappointing thing is Sanchez falls for the first free kick, that's cheating,'' the West Brom manager, who also claimed Mustafi should have been sent off, told Sky Sports.
"Jay is very honest and does not get rewarded. Everyone saw what happened. Sanchez actually dives for the first free kick and he should be booked for diving.
"Then you see the tackle in the box. The referee had a great view. Everyone has seen it and can make their minds up.
"It's not only a foul but the player can be sent off as well. It can be a penalty and playing against 10 men but let's forget about the referee.''
Arsenal scored in the 20th minute when Alexandre Lacazette headed in the rebound from another of Sanchez's free kicks.
They doubled up in the 67th when the Frenchman scored from the penalty spot after Aaron Ramsey was fouled by Allan Nyom.
Discussing the incidents again in his post-match press conference, the 59-year-old Pulis said: "People say Rodriguez is being too honest. Is honesty the thing to do?
"We haven't had a penalty for over a year now. The facts are the facts -- I'm just pleased everyone has seen it.
"I don't want to talk about the referee [or Arsenal's penalty]. We created -- forget the referee's decisions -- lots of opportunities and lots of chances. We've got to put those away.
"I'm pleased in some ways, disappointed in others.''
For his part, Rodriguez felt he was fouled, saying: "For me, I felt contact.
"Obviously I went down and I was just waiting for the foul to be given but it wasn't given so I got back up because I wasn't injured or hurt, I've seen the chance to score and Cech made a good save.
"For me, it was a penalty but you get them and you don't.''