Seeing Pedro Mendes sitting next to namesake and countryman Pedro Caixinha, the new Rangers manager, at the Old Firm game last Sunday reminded me of the time the former Porto player explained their incredible Champions League triumph to me.

Manchester United fans may now be accustomed to seeing Jose Mourinho in the home dugout but perhaps the first time he came to prominence for the majority of them was that incredible night just over 13 years ago at Old Trafford when Costinha pounced in the last-minute after Tim Howard’s fumble to send United crashing out in the last 16.

A goal, of course, that sent Porto boss Mourinho sprinting from the away dugout down the touchline in jubilation. Much to the chagrin of Alex Ferguson.

Portuguese midfielder Mendes, in his only season at Porto, was a key part of only the second team from a country outside the ‘Big Five’ of Spain, England, Germany, Italy and France to win the Champions League. (And there’s a strong argument that Ajax’s 1995 triumph and Porto’s 2004 victory could well be the only ones).

Mendes said the most important factor in that Porto success was the quality available — he namechecked Deco, Ricardo Carvalho, Paulo Ferreira, Benni McCarthy, Derlei and Dmitri Alenichev. And “of course” Mourinho.

But what I most remember from that interview in Glasgow back in 2008 was how he readily admitted there was another key factor involved in Porto claiming the Champions League.

The draw.

Mostly, the quarter-final draw. And the fact any team can be drawn against anyone else.

The draw, Mendes said, just “opened up” for Porto.

They’d put Manchester United out in the last 16 and got Lyon in the quarters. Who they beat fairly comfortably. Meanwhile, in the other quarter-finals, Deportivo La Coruna astonishingly came back to beat AC Milan, Chelsea knocked Arsenal out and Monaco beat Real Madrid.

What happened was the big guns beat each other and Porto were left to dispose of Depor in the semi-final and then Monaco 3-0 in the final — thanks to goals from Carlos Alberto, Deco and Alenichev — after the French side beat Chelsea in the other semi.

“I think Man United was the big test,” Mendes said. “After we put Man United out we were thinking, we can go all the way.”

If ever one of the ‘unfancied sides’ wanted to emulate Porto and claim a surprise Champions League win, then it’s this season after the quarter-final draw.

Of course, there’s a lot of work to do even if you do make the semi-final. But the fact remains that either Bayern Munich or Real Madrid and either Juventus — who of course beat Porto in the last 16 — and Barcelona will not be in the last four.

While Atletico Madrid or Leicester City and either Borussia Dortmund or Monaco will be.

While Atletico, Dortmund or Monaco are strong clubs — Dortmund were 1997 Champions League winners and 2013 finalists, Atleti 2014 and 2016 finalists and Monaco, of course, made the 2004 showpiece — the chances of claiming the big cup are greatly reduced if you face one of the really big guns.

And if Leicester City boss Craig Shakespeare wants to write even more fairytales for the Foxes, he need look no further than Porto in 2004 for inspiration.

Because like then, this season’s Champions League draw has totally opened up the competition.