Saints boss Koeman heaped praise on Pelle's scissor-kick winner as Saints edged out Harry Redknapp's side 2-1 at St Mary's, conceding his surprise at his side's impressive start to the campaign.
Southampton held on to second place thanks to strikes from Pelle and loan man Ryan Bertrand that secured their fourth straight win.
Koeman admitted Southampton have exceeded his pre-season expectations, shaking off Mauricio Pochettino's exit and a raft of player departures.
"I'm a little bit (surprised) by our start yes, because always you have to wait after a lot of changes in the team," said Koeman.
"But we had a good pre-season, we had some difficult moments in the club, a lot of people, even the press was a little bit afraid, with questions about relegation.
"But we know what our qualities are, and little by little we have shown them.
"I'm satisfied with how we're playing
Now we can watch the table tonight and take a picture.
"Then we start again on Tuesday."
Koeman will now hand his Southampton players two days' rest ahead of next weekend's league clash with Tottenham.
Southampton's players turned down a day off on Wednesday in a bid to seize on the good feeling fostered by Tuesday's Capital One Cup victory at Arsenal.
Pelle's acrobatic volley separated the teams on Saturday, the Italian pouncing just moments after Charlie Austin had levelled with an impressive finish for QPR.
Koeman believes there will be few more spectacular Premier League strikes this term than the improvised winner.
"It was a great finish - it will be one of the goals of the season," he said.
"And still it's more important because it made it 2-1.
"I'm happy about his performance from the start of the season, because he has showed his quality and personality.
"He will always keep the ball for the team.
"And that's important for the team in how we play.
"And if you can score like this, you can't do it better."
Rangers boss Redknapp shook off taunts from Southampton fans on his south coast return, owing to his defection from Saints to Portsmouth in 2005.
The ex-Tottenham boss was impressed by Austin's second league goal of the campaign, but admitted his side must sharpen up further in their bid for top-flight stability.
Brazil star Sandro returned after knee trouble only to depart in the opening exchanges due to a heavy blow to the head.
Redknapp allayed fears about any lasting damage, admitting the medics had to remove the holding midfielder as a precaution.
"It was a great finish, he's proved again he can score at this level and that's important and encouraging," said Redknapp.
"We didn't play too badly at all to be honest, but we can still keep improving and we've got to make that progress.
"We were sorry to lose Sandro so early in the game, after a matter of minutes.
"We kept going, kept working, lots to work on and we can keep going.
"He got a bang on the head and the doctor was worried about it.
"He didn't look too bad at half-time, but obviously the doctors have got to err on the side of caution.
"There have been plenty of new directives on head injuries and we just couldn't take any risks at all."
Source : PA
Source: PA