After Keita's superb Premier League debut against the Hammers - in which he was involved in the Reds' opener and made a mazy solo run which could also have led to a goal - Liverpool fans would be hard pressed to disagree with their manager's assessment of the Guinean's talent.
Raheem Sterling opened the scoring with a clinical finish early in the first half and Bernardo Silva's thunderous strike capped a City success that served as a resounding warning to their title rivals.
The Brazil worldwide also, of course, marked his Reds bow with a clean sheet.
In the 80th minute of play, a young Liverpool fan stormed across the pitch with no-one but his idol in his sights.
Moreover, the lack of energy from West Ham'smidfielders did not allow Felipe Anderson to work on the ball for a longer period.
Add Roberto Firmino's hand in setting up Mane's second of the afternoon and it is very much business as usual from Liverpool's front three.
Talk about picking up where you left off.
"But there does seem to be a definite threat from Liverpool at this moment in time, but Liverpool will have to prove that".
They saw off Guardiola's men in the Champions League last season, and a title challenge is now on the cards.
Mane doubled the advantage on the stroke of half time from a James Milner cut-back before adding another shortly before the hour mark.
The 21-year-old, who has played primarily at full-back for the Reds but sees a central berth as his long-term future, responded with a display of confident authority.
One touch is all it takes... Nobody knows exactly how well you did or how worthy your preseason is.
Former Liverpool goalie Ray Clemence reacted to Alisson's performance on social media, tweeting: "Allison, without a lot to do, showed a great presence and looked in control of everything around him".
Has the phrase "immediate impact" ever been more applicable?
The German, though, now has a wealth of options never previously afforded to him as evidenced by the sight of new signings Fabinho and Xherdan Shaqiri plus England internationals Jordan Henderson and Adam Lallana on the bench on Sunday.
How's that for a bench, then?
"The plan is they are all happy because they played an important part in our season, so from my point of view all good".
Let's not forget that three senior centre-backs were absent from the squad altogether, too, with Lovren having played in the World Cup final three weeks ago and Matip and Klavan struggling with injuries.
Nadal topples birthday boy Tsitsipas in Toronto final
Tsitsipas rallied from a set and 5-2 down to turn the tables on Zverev, who had been bidding for a fourth Masters 1000 title. Unlike the other top-10 opponents who fell to the rising Greek star, Rafael Nadal showed why he's the best in the world.
Brendan Rodgers addresses Celtic exit rumours
The midfielder had been widely viewed as the natural successor to Scott Brown at Celtic . 'He wanted to speak to me at 10 o'clock. We're confident going into that game and hopefully we can get the right result. "We will see over the next couple of days.
United Spurs off and running , Football News & Top Stories
But, still those heads didn't bow and but for the frame of the goal, we could have, quite easily salvaged something from the game. We feel so proud about that. "Yes, many good performances from players that were very professional during their holidays".