The Wales international, whose father David played for the Tractor Boys between 1997 and 2001, bagged a first-half double, while Djed Spence and Dejan Kulusevski were on target later on to seal all three points at Portman Road.

Johnson was in the right place at the right time twice in the space of eight minutes to convert a pair of Son Heung-min assists, though Omari Hutchinson halved the deficit before the break with an impressive first-time strike for the hosts.

The result remained in the balance until the closing stages, when a deflected Spence effort and Kulusevski's fine individual goal ultimately condemned Ipswich to a seventh defeat in eight home league matches.

Kieran McKenna's side remains 18th on the league table, but is now five points from safety after Wolverhampton Wanderers' surprise win at high-flying Bournemouth.

Ange Postecoglou's Spurs, meanwhile, stay 12th and are six points adrift of the top 10.

His side is enjoying a welcome upturn in fortunes, which has been inspired by the return of several players from injury.

"The fact that we can throw people on from the bench who can contribute means everyone gets a boost," said the Spurs boss.

"From our perspective, these last two weeks have given us a breather and reset our football. I'm pleased the boys have embraced it."

Postecoglou added: "Ipswich are one of the hardest-working teams in the league. You know you're going up against a battle and a contest – we had to do that.

"First half, we could have done better. We allowed them some moments. But in the second half, we dug in. That allowed us to execute and play our football.

"When you come to a place like this, the crowd creates some energy, so we had to weather that storm.

"But we were always a threat. Sonny [Son] was unplayable in that first half and it's so great to get Brennan back; he scores so many goals for us in those areas."

Spurs remain down in 12th place but Johnson is confident in his side's prospects when it has its best players available.

"He [David] had a great time here and he holds the club in high accounts," Wales international Brennan, who now has nine league goals this season, said about his father.

"For me, it was about getting the three points for Tottenham. They beat us last time and that was in our heads because we didn't want to lose.

"We have always tried to believe. When we have all the players back we have won the last two Premier League games and that's something we wanted to keep in mind.

"We played good football, but also defended well. It's Tottenham Hotspur – we want to be as high as we can. We want to get right up the league."

Ipswich boss McKenna felt there were plenty of positives from his side's performance, but conceded time is running out in the battle against the drop.

"We created more than enough chances, but we have to keep working," he said.

"We know the group is working well in many aspects. To win, we have to improve. There are still improvements in the group.

"There is no doubt they're on a good track, but we're into February and the games start to tick along. We need to pick up points."