The relegation-threatened Welsh club have recorded back-to-back league wins under new manager Paul Clement, including an eye-catching 3-2 victory against City's title rivals Liverpool at Anfield.
Guardiola believes Clement, the former Bayern Munich assistant coach, has made a huge impact and says his own team will have to be at their best to break their visitors down.
"I am really impressed. I saw their game against Liverpool," the City manager told reporters on Friday. "Today I started to watch the game against Southampton. I tried to discover the way to attack them and, wow, I couldn't find it. It's so complicated. When I see their games, I can see his hands on it.”
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City were the only team in the top six to win their mid-week fixture, which saw them move level on points with fourth-place Liverpool, 10 points below leaders Chelsea.
Guardiola faces two key selection decisions over whether to recall goalkeeper Claudio Bravo and striker Sergio Aguero after both were left out of Wednesday's 4-0 win at West Ham United.
Whatever his line-up, Guardiola knows he needs greater consistency from his team if they are to keep pressure on leaders Chelsea and ensure a top-four finish.
"That is the important target for the next round of games," he said. "The last three games I think we were there, especially in the Premier League against Tottenham (a 2-2 draw). We made a huge performance against one of the best teams in the Premier League. In London, against West Ham, we did it again, but that's not enough. We need consistency to win many, many games in a row to be in a position to qualify for the Champions League and, if Chelsea drop some points, to be there."
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Swansea finished a very good January with a 2-1 victory over Southampton on Tuesday and with belief growing that they can end a turbulent few months by escaping relegation.
They go into the weekend in 17th place, two points above the relegation zone and level on points with Middlesbrough and champions Leicester City.
The squad has been strengthened significantly during the transfer window, with midfielder Tom Carroll, left-back Martin Olsson and winger Luciano Narsingh already making significant impacts.
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"Sunderland, Hull, Crystal Palace, Middlesbrough, Leicester and ourselves all have the belief and we are all working very hard to stay in this league," said Clement. "If we keep going the way we are, we will have a big chance."
Forward Jordan Ayew, signed from Aston Villa on Tuesday, has been delayed in joining up with his new team-mates by Ghana's run to the Africa Cup of Nations semi-finals, but will arrive in south Wales next week.
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