Post-match, Ward said: "From my point of view I have got to look at the players' safety. With the rain continuously coming down, the ball holding up and there was obviously a lot of surface water on the pitch, the players' safety has to be paramount and that was the reason for abandoning the game."
Argyle boss Paul Sturrock said: "I felt it was the right decision. I think he should have had a word with the two managers or captains at half-time and marked our cards but if we had played the next 15 minutes - after the decision had been made - it would have been shambolic because of the incredible deluge.
"At the end of the day it was getting bad enough as it was."
Robins said: "That was the best we have played and the players feel aggrieved because they have not got their reward.
"It's disappointing because we played ever so well, we managed to get ourselves a 4-1 lead. The players are devastated. We have got to get over it and we have got to remember that we eventually have to replay it on a Tuesday night.
"It was a brilliant first-half performance - at the end of the day it is irrelevant but I was proud of the players because they gave me exactly what I asked for. Now they have to do it again when we come down here the next time."
The home side got off to a flying start in unrelenting rain when Karl Duguid converted Alan Judge's right-wing cross at the near post from six yards in the ninth minute.
Robins' side restored parity within three minutes as Maltese striker Daniel Bogdanovic sent a diving header past home keeper Romain Larrieu from Adam Hammill's deep cross from the right.
The goals poured in after that, with Emil Hallfredsson making it 2-1 from the left edge of the box in the 16th minute.
Hallfredsson set up Hammill to make it 3-1 with an angled drive from the right in the 24th minute and, six minutes later, central defender Ryan Shotton headed home Hamill's corner from the right.
Sturrock admitted he would have been disappointed if he was in Robins' position, adding: "His team has played very well on the day but my back four allowed their centre-forwards the freedom of the park, whereas our two centre-forwards were shackled and tackled."
Robins revealed that striker Jon Macken suffered a calf injury in the warm-up and was withdrawn to be replaced by Andy Gray.
Sturrock also made a late change, at centre-half, as Kari Arnason suffered a groin injury.