Jurgen Klopp marvelled over a Thiago Alcantara "thunderbolt" but felt Liverpool were somewhat fortunate to beat Porto 2-0 in the Champions League.
Klopp rung the changes for Wednesday's clash at Anfield, with the Reds already through to the round of 16 as Group B winners.
Porto had their chances and were made to pay for their profligacy when Thiago fired home a sublime long-range first-time finish in the second half before Mohamed Salah clinically took his goal tally for the season to 17.
Thiago has endured a frustrating start to his Reds career, but he showed outstanding technique to get off the mark for the season and pulled the strings in the middle of the park alongside Champions League debutant Tyler Morton.
Klopp said of the Spain international's world-class finish: "We had bigger chances in the game than that. Incredible.
"I see that in training, I know he has the technique to do it, but you don't always hit a thunderbolt like that. We needed some moments, some luck, they had big chances on the counter-attack."
Klopp gave key men a rest with qualification already assured and the Liverpool manager expects a stronger showing against Southampton in the Premier League this weekend.
He said: "We could have lost this tonight. We were lucky in moments, yes. We have moments when we're not cool to play against, true, but I didn't expect that tonight.
"I didn't expect a ruthless pressing machine, we grew into the game and that's what I am happy about. We have to play better against Southampton as they are a machine."
The German added: "We had lots to think about, who is injured. who hasn't played, who needs a rest.
"No one felt like they needed a rest as [playing] Saturday-Wednesday the boys are used to that, but it's about the games coming up, so we needed the boys in a rhythm. It all worked out. No injuries, all good."
Liverpool have won all five Champions League matches this season, while Porto remain second ahead of a decisive final group game at home to Atletico Madrid in a fortnight.
Milan, who face Liverpool at San Siro in their last group match, and Atleti are just a point behind Porto after the Serie A side beat the LaLiga champions 1-0.