Quique Setien says he remains positive about Barcelona's hopes of progressing in the Champions League despite Sergio Busquets and Arturo Vidal's absences for the last-16 second leg against Napoli in three weeks' time.

Barca laboured to a 1-1 draw against the Serie A side at Stadio San Paolo on Tuesday, scoring through Antoine Griezmann.

The France international's strike cancelled out a superb first-half goal from Dries Mertens, who limped off early in the second half after a heavy challenge from Busquets.

That foul earned the holding midfielder a yellow card, which rules him out of the second leg, while Vidal will also sit out the clash at Camp Nou after receiving his marching orders for quick-fire cautions in the same incident with Mario Rui late on.

Setien is not despondent, though, and is confident his side – who also lost Gerard Pique to injury late in stoppage time – will have enough firepower to overcome Gennaro Gattuso's men.

"We will look for solutions," he told a media conference.

"We have lost important players, but we will recover two others – Jordi Alba and Sergi Roberto. We have to look at things with optimism. We will be optimistic and think positively."

Setien refused to blame his players for their lacklustre performance, instead preferring to criticise what he perceived to be a negative display by the hosts.

"It is a good result considering that we have a return game at home," he added.

"They have defended with 10 players very close to their area. It is true that we have not generated much, but we knew that it was a matter of patience.

"It has been a close match and I consider it fair. We have had control, but in the first half they defended well and took advantage of the only occasion they had.

"The second half was different; there were more spaces and we have done more damage. A 1-1 draw is fine for the second leg."