Archer spent 17 months on the sidelines with back and elbow injuries before returning to international cricket in the one-day series in South Africa.
His career-best 6-40 helped secure England's 59-run victory in Wednesday's third one-dayer in Kimberley, though South Africa won the series 2-1.
"Being back after however long, it's kind of surreal," Archer said after England snapped a five-match winless streak in ODIs.
"You only get that feeling after you start playing. It's definitely gone up a few notches.
"It's just a long road, this is a small tick but I want to see how I am in April, June, July and September. This is just the start of the road."
Archer bled 81 runs for the lone wicket of lower-order batsman Wayne Parnell in the series opener against South Africa.
But the 27-year-old was at his menacing best on Wednesday - destroying stumps, hitting Aiden Markram with a bouncer and regularly exceeding 90 miles per hour.
"It was fantastic and probably deserving of the player of the match award," captain Jos Buttler, who bagged the honour for his blistering hundred, said of Archer's display.
"When the game was in the balance, to come back there and take the wicket of (Heinrich) Klaasen broke the game open for us."
England will hope a fully-fit Archer will help them reclaim the Ashes from Australia and retain the 50-overs World Cup title in India later this year.
"He is a graceful fast bowler and it is so good to have him back in international cricket," former England captain Nasser Hussain told Sky Sports.
"He is like gold dust and needs looking after. He is so valuable for English cricket and world cricket. He is so box office."
