Cristiano Ronaldo's streak and Firmino's away-day success

The Champions League returns this week and the tie of the round sees Real Madrid host Paris Saint-Germain in the opening leg of their last-16 clash on Wednesday.

Well off the pace in LaLiga, Madrid's sole remaining hope of capturing significant silverware this season comes in Europe, as Zinedine Zidane's side look to lift the famous trophy for the third time in succession.

But PSG, runaway leaders in Ligue 1, have Neymar in their ranks and the Brazilian, alongside the lethal Edinson Cavani and Kylian Mbappe, would love to get one over on Barcelona's fierce old foes.

Wednesday's other tie sees Liverpool travel to Porto. The two clubs tasted Champions League glory midway through the previous decade but have found success harder to come by since those heady days.

With the help of Opta, we crunch the numbers ahead of the first legs of two fascinating ties.

Real Madrid v Paris Saint-Germain

10 - Under Zidane, Madrid have won 10 of their 14 Champions League knockout games (D2 L2), lifting the trophy twice in as many seasons. As part of this run, they've won all six of their games at the Santiago Bernabeu.

0 - PSG have not progressed further than the quarter-finals in the last five Champions League seasons. Their best performance to date is a semi-final in 1994-95, when they were eliminated by AC Milan.

2 - Last season, Madrid became the first team since Inter in 2010 to win the Champions League after finishing second in their group.

4 - PSG have lost four of their last six away games in the Champions League knockout stages, winning one (2-1 v Chelsea in March 2016) and drawing one.

19 - Top scorer in the history of the Champions League (114 goals), Cristiano Ronaldo has netted 19 times in his last 11 appearances in the competition, including in every single game this season.

Porto v Liverpool

4 - Liverpool were one of four teams to remain unbeaten in this season's group stages, alongside Barcelona, Besiktas and Tottenham.

3 - Porto have lost their last three Champions League knockout games (one goal scored, nine conceded).

23 - Only PSG (25) scored more goals than Liverpool (23) in the group stages. The Reds also had more touches inside the opposition box than any other team (251).

8 - Porto scored more goals from set-pieces (eight) than any other team in this season's group stages.

9 - In his first six Champions League games, Roberto Firmino has scored six goals and delivered three assists. Also, no player was directly involved in more goals than Firmino away from home in this season's groups (four goals, two assists).