The two teams lock horns in the Premier League on Tuesday, and Guardiola is expecting a tough test for his side who can go top of the table with a win.
In stark contrast, the Baggies are scrambling for points in a bid to get themselves out of the relegation spaces.
In Allardyce, West Brom have a manager who is well versed in fighting relegation battles and was set a task of keeping the club up when he replaced Slaven Bilic in December.
Guardiola feels it is difficult to take the reins in the middle of a season, adding that he has huge admiration for the work Allardyce has done throughout his career.
“It is not easy to take over a team during the season, but against Wolves, Liverpool, other clubs, he got good results,” Guardiola told Sky Sports . “Sam Allardyce is a genius to take these teams when everyone believes it is over and get results.”
Since his appointment on December 16 , Allardyce’s West Brom have had some mixed results. They were thrashed 5-0 and 4-0 by Leeds and Arsenal respectively, but also beat Wolves and got a draw against Liverpool.
Guardiola feels those positive results are an indicator of the work Allardyce can do and feels they will boost the players’ confidence.
“The results give you an incredible boost, an incredible confidence,” Guardiola said. “What is first – do results make you play good, or do you play good if you get results? I think both are connected.
“We are just at the end of January, so it is just West Brom, trying to analyse them and make a good game to get another victory.”
A win would propel City to the top of table, above Manchester United, but Guardiola feels it is too early in the season to be focused on the standings.
“The leader is United,” he said. “They are top of the league. The moment we have all games together we will see.
“Now we are not top of the league and the difference [to] third, fourth, fifth and sixth is so close, so narrow. But I didn’t look at the table much when we were 12th and eight or nine points behind the leaders, and now is the same.”