The Champions League is back with matchday three and the group stages are shaping up nicely.

Teams are preparing for back-to-back fixtures so a lot could be decided as we reach the halfway point.

Here, Press Association Sport takes a look at the main talking points ahead of this round of fixtures.

Ronaldo reunion for under-fire Mourinho

Having served his ban in the previous round of games, Cristiano Ronaldo is available to enjoy an emotional return to Old Trafford as Juventus visit Manchester United. Ronaldo was a hero in the red half of Manchester and helped them win the competition 10 years ago, while he is also coming up against his former boss Jose Mourinho, who managed him at Real Madrid. Mourinho will be desperate to win for his own sake as the spotlight remains firmly on him, especially after the ugly scenes at Stamford Bridge on Saturday when he became involved in a touchline fracas following Chelsea’s late equaliser. This double-header is likely to decide who will win the group, so it is an important game.

Must-win for Tottenham

Having capitulated in the final 10 minutes against Inter Milan to lose 2-1 and then being given a footballing lesson by Barcelona at Wembley, Tottenham’s Champions League campaign is on the ropes already. Spurs won a tough group including Real Madrid last season, but this time round second place is the best they can hope for and if that is possible then their trip to PSV is simply one they have to win. Mauricio Pochettino has rested players in the opening two games but that might not be possible against the Dutch side who have also lost their opening two games.

Messi-less Barcelona missing for heavyweight clash

All eyes will be on how Barcelona can cope without Lionel Messi, who is sidelined with a broken arm when they visit Inter Milan. The Argentinian’s importance needs no highlighting and he should be a big miss at the Nou Camp as two European heavyweights go head-to-head. Inter, who snatched a last-gasp Milan derby win on Sunday, have also won their opening two games and if they can get a result in Spain, it would go a long way to booking their place in the knockout stages on their return to the competition.

Liverpool have to go big

Liverpool have run into a tricky spell over the last month and recorded their first win in five with a scrappy win over Huddersfield on Saturday. That run of results included a 1-0 loss at Napoli in the Champions League, which blew Group C wide open. With Paris St Germain also in their pool, the race is on to finish in the top two and it could come down to goal difference. The French side hammered Red Star Belgrade 6-1 last time out and Liverpool will be targeting a similar sort of scoreline at Anfield.

Lopetegui’s last stand?

The vultures are circling around Julen Lopetegui as he endures a nightmare start to life as Read Madrid head coach. The former Spain manager has overseen defeats in four of the last five games, including a shocking home defeat to Levante in LaLiga and a surprise loss to CSKA Moscow in the Champions League. It all means that even a comprehensive Group G win over minnows Viktoria Plzen at the Bernabeu might not be enough to save him.