After three years away from the club, the Baggies controlling shareholder surprised everyone by holding meetings with Ismael and other key staff during a surprise visit three weeks ago.
Those talks were the start of Lai reintegrating himself back into the club with the businessman also attending Albion's draw with Cardiff on Sunday.
The Baggies signed Dike from Orlando City for a fee believed to be in the region of £7million on the first day of the January transfer window.
And Ismael revealed Lai gave the green light to sign the striker on a permanent basis after accepting his team needed more fire power to compete with Fulham, Bournemouth and Blackburn – with those sides all having prolific strikers in Aleksandar Mitrovic, Dominic Solanke and Ben Brereton Diaz.
"It was team work – we've been working on the deal over the past few months," Ismael said.
"We prepared very well for the transfer. We recognised quickly that we have struggled to convert our chances and we knew we needed someone capable of scoring goals.
"If you look at the minute which players are scoring the goals, it’s a Fulham player, a Bournemouth player and a Blackburn player.
"We needed to do something and I think the game changer was the meeting with Mr Lai at the training ground. We spoke about the situation, we explained exactly what we needed, why we need it and our vision long-term.
"I think it was important he understood everything and he got the feeling that we know exactly what we wanted and that always makes things easier.
"When you know exactly what you want, you need to be patient but at least you can give all your energy to getting the result.
"We got the result with Dike. We wanted a striker that can score goals and to get him in the first few days of the window. It's also a permanent transfer so it means we can work with the player over the next few players."
Having scored nine goals in 19 appearances for Barnsley last season, Dike is under pressure to be the goalscorer Albion desperately need.
But Ismael says he and his team will do everything they can to give the striker a platform to perform – with the boss confirming Dike won't be involved in Saturday's FA Cup game with Brighton.
"It’s his job now to score goals but it’s my job with my staff to prepare him," Ismael said when asked how Dike will cope with the pressure of leading Albion's line.
"He got four weeks off due to the MLS season being finished. We need to prepare him for the Championship, a small pre-season if you like.
"We have now got two weeks to prepare him for the game against QPR.
"But it’s not just these two weeks, we want to build him up throughout January because we will have a lot of games so we have to make sure Dike can stay stable in his performance."