England manager Sarina Wiegman says Beth Mead "started shining" when she came on as a substitute to score a hat-trick in 14 minutes at Wembley Stadium.
Mead scored seconds after coming on in the 74th minute to give England the lead against a stubborn Northern Ireland side.
Fellow sub Bethany England also got on the scoresheet as England comfortably won their World Cup qualifier 4-0.
"Of course she feels good, that we can see," said Wiegman.
"I'm really happy for the team that she scored three goals, and for her especially. The players feel comfortable so players can shine. She started shining when she came on so did a really good job.
"Today was a pretty hard game but we are working together, feeling good and we just want to go forward and forward."
Mead has been in terrific form for Arsenal and England - netting four goals in her past three internationals - and Wiegman says she showed her confidence with her performance against Northern Ireland.
"She's in a very good place at the moment and it's obvious she is a good footballer. She feels really good and showed that on the pitch and does in training and with Arsenal," Wiegman added.
"I'm going to make an agreement that we do that every game - we bring on a player and they score three times! I'm just kidding, but it's really nice.
"It's what you need to get to a higher level and win matches. It doesn't matter who scores, we just need to score, so when you bring on a new player, you maybe do something different and then it's really nice that we get a result with that."
Wiegman will have a selection headache for Tuesday's game against Latvia but the Dutchwoman insists she is "really happy" to have depth in the squad.
"We brought some new players on the pitch and they made a difference," she added. "This team has depth and we have to pick and choose many players for the squad.
"I'm probably a little lucky. They were really ready to go in. That's what the team needs. When the substitutes come on they have to be ready and that's absolutely what they showed."
'One of my proudest moments'
Mead posed for photographs on the Wembley pitch after the England players were applauded on a lap of honour at full-time.
Several fans stayed behind to shout her name afterwards too, while family members waved from the boxes high in the stadium.
"Even to score a goal at Wembley is an amazing feeling," Mead told ITV. "It's an honour to put this shirt on and score for my country, but to score a hat-trick is a special feeling and I'm glad to help the girls get three points today.
"[Wiegman] just told me to go out there, enjoy it and make a difference - hopefully I did that! Sarina has confidence in every single one of us.
"I think it's got to be up there [as a career highlight]. To score a hat-trick at Wembley for your country is probably one of the proudest moments for me and my family."
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