MANCHESTER, England, Dec 5 (Reuters) - Back-to-back Premier League wins have rejuvenated Manchester City's bid to catch up with leaders Arsenal, but a leaky defence has manager Pep Guardiola worried ahead of Saturday's home clash with Sunderland.

City beat Leeds United 3-2 last weekend before Tuesday's 5-4 win at Fulham, where Guardiola's men conceded three goals within 21 minutes after taking a four-goal lead.