Adams' men appeared to be cruising towards an easy win before struggling Tranmere netted twice in two minutes to set up a grandstand finish.
There were chances galore in a contest which could have yielded many more goals, but Adams was nevertheless a very happy man after seeing Vale reach the 50-point mark after hanging on to a 3-2 win.
He said: "They could give me a heart attack at times, but we've got to 50 points and that's a fantastic achievement for this group of players.
"Our next target is 53 points and we'll try to win as many of the remaining games as possible to finish as high up the league as possible.
"We were comfortable at 3-0 and then we are on a knife-edge because the Achilles heel we have had all season returned.
"I've never managed a team who have conceded so many goals from set pieces. We've worked hard to try to put that right but it's still happening.
"The first one from the corner is a good header by their big centre-half (Ash Taylor), but we've got to defend much stronger than that and it's disappointing.
"But I still want to pay tribute to my players for their efforts this season and I think we deserved our win. Tom Pope and Ben Williamson have caused Tranmere's defenders a lot of problems and we should have scored more goals."
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