'Players worried for families': Fan trouble mars Wolves win at West Brom
Play was halted by referee Thomas Bramall late in the second half at the Hawthorns when fans spilled onto the pitch as fighting broke out in one corner of the stadium.
One supporter was escorted away with blood streaming from a head wound.
Play resumed after a delay of 38 minutes and the final 12 minutes of Wolves' 2-0 win were finished with no further incidents.
The ugly scenes came in the first meeting between the bitter rivals with fans allowed in 12 years.
Violence broke out on a large scale shortly after Matheus Cunha had given Wolves a two-goal lead over their 'Black Country' neighbours in the 78th minute of the fourth-round clash.
West Brom hooligans appeared to attack Wolves fans who were sitting in a section of the Hawthorns reserved for home supporters.
Police and stewards rushed to the disturbance as missiles and punches were thrown at both ends of the ground.
The teams left the pitch to return to the dressing rooms, with West Brom defender Kyle Bartley holding his child in his arms after taking him from an area near the trouble.
There had earlier been pockets of trouble in other parts of the ground.
Fans threw flares in the away section after Wolves opened the scoring in the first half. Objects were also thrown at Wolves' Tommy Doyle as he prepared to take a corner.
West Brom captain Jed Wallace admitted the shocking scenes had taken a toll on his side.
"You focus on the game and then it's kicking off. A lot of the players were distressed because that's where their families sit," he said.
"They were worried about their children, that's why you could see some of them running over. No-one wants to see that in football.
"They're two huge clubs with passionate supporters. You hope it keeps a lid on it at times.
"The game was played in a good spirit on the pitch. You fly into tackles and shake hands after."
Speaking after his club's first win at the Hawthorns since 1996, Wolves goal-scorer Cunha insisted he never felt threatened by the violence.
"I'm from South America, this kind of thing happens, as long as everyone is safe," he said.
"It is bad when you see some children crying and things like that, but the most important thing is everyone is safe.
"Derby days are always incredible, the atmosphere is amazing. After 2-0 it was calm. We came back out for the final 10 minutes and got the win."
West Brom are certain to face a Football Association probe into their handling of the clashes, with questions set to be asked over how Wolves fans were able to get tickets in the home end.
