Rangers have been praised by Porto legend Jorge Costa after he warned his old club they will have to raise their game to qualify for the next round of the Europa League .
Steven Gerrard's side returned from Portugal with a highly creditable 1-1 draw against Porto last week and will play them at Ibrox next week.
And Costa - who won 24 trophies with Porto including the Champions League and UEFA Cup - knows Porto cannot afford another performance like last week when they travel to Glasgow.
Costa, who is now manager of Indian side Mumbai City, said: "Porto are now in a situation where they cannot relax at all in their Europa League group.
"I watched the game against Rangers and the Scottish side were really good. That result and performance from that match now has very unpleasant consequences for Porto.
"By this stage in the group, a club like Porto should have already have more or less secured qualification, but they cannot relax now.
"If they were to drop more points in Glasgow - or worse, lose - they would be in serious trouble.
"It means they cannot rest players for the league and they have to keep playing their strongest team. They have to show maximum concentration in Scotland.
"Porto will have the chance to put that performance at home to Rangers to one side when they play the second game against them. But it won't be easy and they must accept they will get a very hard game there."
