The Championship side won 36-12 at the Recreation Ground to make the sixth-round draw of the Challenge Cup, leaving Whitehaven to concentrate on League One.
“We did very well and were really only let down by our discipline towards the end of the first half when we gave away too many penalties,” said Forster.
“We threw a few things at Halifax in the second half, and, to be fair, they handled them well.
“But it was only 12-6 to them over the 40 minutes.
“They are a good Championship side and will be in the top four at the end of the season. So, we can take a bit of heart in our performance."
“It’s always good to test yourselves against teams from a higher level and we did well," Forster added.
“The fact we turned round 24-6 behind didn’t help our cause but we battled really well with them after half time.
“We have a big week ahead, with the re-arranged match at Hunslet and it could decide who goes third in the table. We are all looking forward to it."
Haven had gone into the game with doubts over several players’ fitness and in the end Scott McAvoy, Glenn Riley and Aiden Worthington all missed out on the 17-strong squad.
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