"It's nice for the fans and everyone who loves the [club] but as a manager, and as technical staff, we have to keep quiet and continue what we are doing," Koeman told reporters.
"There is no time to celebrate or watch the table too much. Football changes very fast and you have to prepare yourself that way. It was a different win; a tough one, a difficult one against a strong Swansea. After the [sending-off], it changed.
"Always those kinds of decisions of the referee are difficult for one [team] and better for another. We had the patience to wait, create the positions and score a great goal. I said at half-time: 'the worst result is 0-0, wait for the moment and be patient for the real good moments to create'. We didn't do it often but once or twice was enough."
Southampton travel to the Emirates Stadium to take on Arsenal in the League Cup on Tuesday night.