Hamburg - There is all to play for in the Champions League after Tuesday night's first-round matches in the round of the last 16 failed to produce any clear winners.
Inter Milan were held to a goalless draw by Manchester United in Italy, Barcelona played to a 1-1 draw at Olympique Lyon, and former winners Porto drew 2-2 in Madrid against Atletico.
The only victory on the night belonged to Arsenal, who missed a number of excellent chances against AS Roma but still registered a 1- 0 victory through Robin van Persie's first-half penalty.