Champions League: Man City and Arsenal resume battle

Barcelona are looking for a record eighth consecutive quarter-final spot

It's mid-February, which means one thing - the return of the Champions League, and the point where it really starts to motor.

We have already seen the first legs in four of the eight ties as Paris St-Germain drew 1-1 with Chelsea,Shakhtar Donetsk frustrated Bayern Munich in a goalless draw, Real Madrid won at Schalke 2-0 and Porto drew 1-1 with Basel. BBC Sport picks out the key factors in the other four games.

City must make home advantage count

Manchester City v Barcelona (Tuesday, 24 February)

Barcelona beat Manchester City 4-1 on aggregate at the same stage last season

It is one challenge down, one to go for Manuel Pellegrini. Many felt the Chilean's position at the Etihad could be compromised by a Champions League group failure, but a masterful display in the crucial match away to Roma responded to his critics.

Last season, Pellegrini seemed to learn from his tactical failings in the home match with Bayern by the time it came to facing Barcelona at this stage, but he needs to make sure City do not lose the tie in the first leg like they did last year.

City's organisation in that game was to be applauded but it was at the expense of their trademark attacking flair.

It is possible to get at Barca in wide areas with pace, and PSG's win over them in September is a good template; be solid, be physical from attacking set-pieces, keep your shape and realise it is not necessarily about individuals - Blanc's team won that game minus Zlatan Ibrahimovic.

Struggling Dortmund cannot be underestimated

Juventus v Borussia Dortmund (Tuesday, 24 February)

Borussia Dortmund players went over to appease fans after a recent defeat by Augsburg

Dortmund's domestic struggles have confounded many, but the difference between their Bundesliga travails and their good European form is a question of tactics.

Jurgen Klopp's side like to counter-attack, whereas they are less comfortable when expected to make the running (only Bayern have greater average possession than Dortmund in the Bundesliga).

This is where the main danger to Massimiliano Allegri's Serie A leaders lies in this repeat of the 1997 final, won by die Schwarzgelben (Black and Yellows) with future Liverpool striker Karl-Heinz Riedle scoring twice.

Only Bayern and Barca enjoyed more than Juve's 61.1% possession in the group stages, which will suit Dortmund down to the ground. Giorgio Chiellini and company will need to not over-commit and guard against the pace of Pierre-Emerick Aubameyang in particular.

Monaco will be a tough nut for Arsenal to crack

Arsenal v Monaco (Wednesday, 25 February)

Arsenal lost 1-0 to Monaco in a pre-season friendly with Radamel Falcao scoring the goal

If Arsenal fans are thinking that they lucked out in this year's draw after being lumbered with Bayern and Barca in recent seasons, they might want to reconsider.

Arsene Wenger's former club are not quite on that level and cut less of a swagger since the exits of James Rodriguez and Radamel Falcao, but they are no pushovers.

Leonardo Jardim has developed a cautious game-plan since arriving to replace Claudio Ranieri as coach, and no team let in fewer goals than Monaco in the group stage (just one).

This is no anomaly; goalkeeper Danijel Subasic recently completed 842 minutes without conceding and the Gunners will need to be at their most patient, whether Ricardo Carvalho makes it back from injury in time or not.

With Monaco having scored just four in the group, this promises to be tight.

Simeone still has his magic

Bayer Leverkusen v Atletico Madrid (Wednesday, 25 February)

Atletico Madrid are still in the race for the Spanish title and Champions League

Many expected the Spanish champions to fall apart in the wake of last season's heartbreaking final defeat by neighbours Real Madrid in Lisbon, especially when Diego Costa, Thibaut Courtois and Felipe Luis all went.

But their coach Diego Simeone has kept them fiercely competitive. Atletico remain in the hunt for major honours, winning both Madrid derbies in La Liga and taking four points from Juve on their way to winning the group stage.

Leverkusen started the season at locomotive speed under coach Roger Schmidt but will press high at their peril here. The in-form Antoine Griezmann has the pace to catch the Bundesliga side out, while the revival of Fernando Torres - a former Atleti team-mate of Simeone - is further testament to Simeone's powers

He is showing signs of forming a good alternative front pair with Mario Mandzukic.

Champions League last-16 second leg tie: Tuesday 10 March; Porto v Basel, Real Madrid v Schalke. Wednesday 11 March; Paris St-Germain v Chelsea, Shakhtar Donetsk v Bayern Munich. Tuesday 17 March; Atletico Madrid v Bayer Leverkusen, Monaco v Arsenal. Wednesday 18 March; Barcelona v Man City, Borussia Dortmund v Juventus.