MADRID, April 28 (Xinhua) -- Atletico Madrid faces Arsenal at the Metropolitano Stadium on Wednesday in the first leg of their UEFA Champions League semifinal, in a rematch of the league phase meeting that Arsenal won 4-0 in London in October.

Since then, Arsenal's imperious early-season form has dipped, with Mikel Arteta's side now locked in a tight Premier League title race with Manchester City.

Injuries have also taken a toll. Mikel Merino is a long-term absentee and is doubtful for the World Cup, Jurrien Timber is sidelined with a pelvic problem, and Kai Havertz picked up a groin injury against Newcastle United last weekend. Eberechi Eze and Martin Zubimendi were also forced off in that game, with Eze a doubt for Wednesday.

The main boost for Arsenal is the return to fitness of Bukayo Saka, who has shaken off Achilles trouble and will add attacking threat against an Atletico team likely to defend deep and play on the break.

Atletico sits fourth in La Liga, comfortably clear in the race for next season's Champions League but out of the title picture. That has allowed Diego Simeone to rotate since the Copa del Rey final defeat to Real Sociedad, giving key players such as Ademola Lookman, Julian Alvarez and Giuliano Simeone time to recover. All three are expected to start, although Lookman is nursing a groin issue.

Wednesday promises to be a tactical game, with both sides capable of sitting in a low block and both dangerous from set pieces. A single goal, perhaps from a corner, could decide the first leg, but the tie is likely to be settled in next week's return in London.

If that is the case, Atletico will be satisfied, with Simeone able to rest players in La Liga at the weekend, while Arsenal face no such luxury as they host Fulham in a crucial Premier League fixture. ■