Former City midfielder Howey admits he was surprised all four English teams made it through - especially United and Liverpool.More news: DraftKings fantasy golf picks: The Players Championship 2019
"In previous years, we have always had the belief that the Premier League is the best in the world".
Barcelona, however, beat Juventus in the Champions League final in 2014/15, winning 3-1 in Berlin, with goals from Ivan Rakitic, Luis Suarez and Neymar.
"The calendar for the semi-finals (including a potential reversal involving Manchester United FC, for the same reasons, if both clubs from Manchester are still remaining in the competition) will be communicated to all parties on 18 April 2019, following the return legs of the quarter-finals". "But it has been a top league and there haven't been that many teams [in the latter stages] of this one".More news: Saudi kingdom pursuing justice in Khashoggi murder, says official
"We know that. People will look at Porto and Ajax [as weaker], but they are young teams and they are flying".
Tottenham were the first of the English teams to book their spot in the last-8 this season after they brushed aside a muted Borussia Dortmund.
Pep Guardiola's free-scoring City are the favourites with the bookmakers after their 10-2 aggregate thrashing of German club Schalke in the last 16. Ronaldo's never even been on the losing side against English opposition in the knock-out stages of the Champions League even dating back to his time at United, when Sir Alex Ferguson's men overcame the likes of Chelsea and Arsenal in all-English encounters. They have undoubtedly got the quality and the confidence at the moment. It will be hard, but not impossible.More news: Gold prices dip on dollar recovery over Brexit relief
They have also played twice in European knockout stages and, while Porto eliminated the Blaugrana in 1972/73, the 1985/86 tie had the opposite result.