Mark Warburton last month he set himself the ambitious but "realistic" target of winning the Scottish Cup.
When the 46-year-old Portuguese signed a three-year contract to replace Mark Warburton last month he set himself the ambitious but "realistic" target of winning the Scottish Cup and overtaking Aberdeen to claim second spot.
For the Rangers support second is usually nothing.
However, with Celtic having already clinched a sixth successive league title and chasing a domestic cleansweep, the runners-up spot is all they have to play for in the league as they chase a European place.
Caixinha's hopes received a boost as he got off to a flyer with a 4-0 thrashing of Hamilton in his first game in charge.
However, it has proved to be something of a false dawn and draws with Motherwell and then Kilmarnock mean Rangers trail Aberdeen by 12 points as they head into the powderkeg clash.
Caixinha admits that just three games into his career in the Scottish top tier it's win or bust for his side.
"It's getting difficult. We know we need to play twice against Aberdeen and that they have to play against all of the top six again," he said.
"The maths says it can still be done but the next game will be crucial to understand if we are able or not."
"If we don't win on Sunday against Aberdeen, we don't deserve to be in second positon. But that is my challenge. It is something we need to prove to ourselves."
Rangers will face an in-form Aberdeen side that has won 15 out of their last 16 matches and recently set a new club record of 10 consecutive wins at Pittodrie -- surpassing Alex Ferguson's great Dons side of 1986 -- as they close in on a record points haul for the club.
Aberdeen defender Anthony O'Connor revealed there is a great desire in the Dons dressing room to make Caixinha eat his words from his first day in charge when he suggested he could beat Aberdeen to the runners-up spot.
"It is easy saying that but they would have to come and beat us twice," the 24-year-old Irish defender said.
“It isn’t going to be easy. Him saying stuff like that doesn't bother us too much because we just go on to the pitch and do our business."
"It galvanises us to win more when people are talking about us like that."
"Every time I watch the news it's people talking about Rangers and Rangers catching Celtic."
"But we are the ones who are in second and people should be talking about us a bit more."
"People probably wrote us off at the start of the season but we have shown how good we have been all season."
Fixtures (1400GMT unless otherwise stated)
Celtic v Kilmarnock, Hamilton v Ross County, Hearts v Dundee, Inverness CT v St Johnstone, Partick Thistle v Motherwell
Aberdeen v Rangers (1130)