The two-goal striker helped his side to their third league win in succession in the match at Portman Road.
The victory, capped by teenage striker Matthew Paterson's first senior strike, took Saints within two points of moving out of the bottom three.
Head coach Wotte said: "Jason Euell has done fantastically for us tonight. I am pleased with him.
"When I started this job, I gave him three times a substitute role, and every time he had a good impact - so I put him in the first XI.
"His contract is expiring, so he has personal reasons to play well. He feels confident, like most of the players, and he has done brilliantly."
Despite securing nine points out of nine - with two wins at home and one on the road - Wotte insists his side remain deep in the relegation mire.
"It was, for me, very important that everyone recognised the important situation we are in," he said.
"We have five games in 12 or 13 days. We have to be mentally very strong and also physically.
"Two home games don't make us survive in the Championship - neither does this victory. We are still in trouble.
"We have to be serious - because it's a serious situation."
As well as scoring three goals, Southampton also had further efforts from defenders Chris Perry and Jan-Paul Saeijs disallowed for fouls.
"We scored five goals tonight," added Wotte.
"I think the referee saw something that I did not see."
For Ipswich, with one win in seven home league games, the defeat put a huge dent in play-off hopes.
The Blues are now five points adrift of the top six, having played more
games than many of their rivals.
Manager Jim Magilton could not disguise his disappointment at his side's "worst performance" in his three years in charge.
"It's certainly the worst performance since I became manager, without a shadow of a doubt," he said.
"It was three (nil) going on six.
"It was not acceptable. The crowd had every right to voice their opinion tonight.
"You have to have a few words after a performance like that. You want to know where it has come from. You want to know which players are going to stand up and say a few words."
Magilton refused to accept blustery conditions might have been to blame for the poor showing.
"There's absolutely no excuses, because at times they passed the ball - we couldn't string two passes together," he said.
"We didn't look as if we had a goal in us.
"It has stunned the life out of me. I didn't see it coming."