Swindon boss Paolo Di Canio hailed goalscorer Jonathan Smith, saying he knew he found a gem after watching the midfielder on YouTube.
Goals either side of half-time from substitute Smith and Algerian striker Mehdi Kerrouche condemned Southend to a 2-0 defeat.
Di Canio said: "He can really play and do his part. When you watch him play, he is always looking to attack and tracks the edge of the box. He really presses forward well.
"I'm not surprised that he scored. It was a fabulous strike and he is developing nicely."
The Robins boss also lauded the performance of midfielder Alan McCormack, who filled in as an emergency defender from the 15th minute when Oliver Risser was forced off with a knee injury.
Di Canio added: "I told McCormack to be ready on Friday because we had a slight concern about Oliver. He is really intelligent and won every ball that came his way. We were a little under pressure, but the desire of the players and Alan's reading of the game was excellent."