María Luisa ("Magüi") Serna Barrera (Spanish pronunciation: [ma'?i.a 'lwisa 'ma?wi 'se?na ßa're?a]; born 1 March 1979) is a former tennis player from Spain.
She started competing in ITF Challengers as from 1993, and joined the WTA Tour in 1996.
On 12 January 2004, she reached her career-high singles ranking of world No.
19.
Serna produced an upset by defeating Justine Henin in the 2001 Scottsdale tournament, 7–6, 7–6.