Striker Mileta Rajovic nodded home a late winner for Watford as they claimed a 3-2 victory in a dramatic opener at Millwall.

The Lions thought they had fought back to at least take a share of the spoils with two second-half goals from Duncan Watmore after Edo Kayembe and Giorgi Chakvetadze had put Watford firmly in control.

Millwall paid their respects to goalkeeper Matija Sarkic, who died aged 26 in June. The Montenegro international’s family were at The Den, with Lions captain Shaun Hutchinson and opposite number Moussa Sissoko laying wreaths in the centre circle before a minute of rousing applause.

A video montage of Sarkic’s saves was also played shortly before kick-off.

Watford absorbed some early pressure before taking a 22nd-minute lead.

Millwall’s debutant goalkeeper Lukas Jensen had just turned Ryan Andrews’ low attempt around a post but then Kayembe’s corner curled directly into the net.

Midfielder George Honeyman’s shot struck the left-hand upright in the 37th minute and a second attempt was cleared off the line by Francisco Sierralta as Millwall responded.

The home side went close again at the start of the second half when George Saville’s header from a Honeyman free-kick crashed back off the right-hand post.

Chakvetadze doubled the Hornets’ lead in the 55th minute with a superb free-kick from 30 yards. The Georgia international had been awarded the foul with Ryan Leonard booked for halting his counter-attacking surge.

More drama was to come as Watmore’s brace hauled Millwall level.

The former Sunderland and Middlesbrough forward halved the deficit in the 74th minute when his finish clipped in off the crossbar from inside the six-yard box after substitute Aidomo Emakhu’s cross was only partially blocked.

Millwall regained parity with two minutes of normal time remaining. Watmore arrowed a quality low effort past Watford goalkeeper Daniel Bachmann from Saville’s clever switch of play.

But Watford’s response was almost instant. Substitute Rajovic deftly headed in after Tom Dele-Bashiru’s shot took a deflection to fall kindly into his path.

It is the first home defeat suffered by Millwall head coach Neil Harris since he returned to the club in late February and is also the first reverse for the south Londoners on the opening day in seven seasons.

Watford won their campaign curtain-raiser for a fifth season in a row.