The fact that the 1999 squad only ever won one CL would suggest there was room for improvement. A lot of United fans feel the side with Rio, Vidic, Ronaldo, Tevez, & Rooney was the best ever. Sometimes it's all about luck & timing. Where the 99 United were only a penalty save away from going out in the FA Cup semi-final, & then Juventus switching off in the CL semi final, plus 2 very late goals in the final. The United side of a decade later were unlucky they came about at the same time Barca's greatest team ever were around. 2 very good Manchester United sides. Difference being is that the cards fell nicely for the 1999 team, whereas Pep's Barca held all the aces up their sleeve 10 years later. So in keeping with the theme of the thread, I believe that if Guardiola sticks around for some time at City & sees off Klopp, then his luck will eventually turn in the CL. I wouldn't be at all surprised to see City become the dominant European force that Liverpool were in the 70's & 80's, & his Barcelona side were not so long ago.